NGHTTPX(1)

NAME
nghttpx - HTTP/2 proxy

SYNOPSIS

nghttpx [OPTIONS]... [<PRIVATE_KEY> <CERT>]

DESCRIPTION

A reverse proxy for HTTP/3, HTTP/2, and HTTP/1.

<PRIVATE_KEY>
    Set path to server's private key. Required unless "no-tls" parameter is used in --frontend option.

<CERT>
    Set path to server's certificate. Required unless "no-tls" parameter is used in --frontend option. To make OCSP stapling work, this must be an absolute path.

OPTIONS

The options are categorized into several groups.

  Connections

-b, --backend=(<HOST>,<PORT>|unix:<PATH>)[;[<PATTERN>[:...]][[;<PARAM>]...]
    Set backend host and port. The multiple backend addresses are accepted by repeating this option. UNIX domain socket can be specified by prefixing path name with "unix:" (e.g., unix:/var/run/backend.sock).

    Optionally, if <PATTERN>s are given, the backend address is only used if request matches the pattern. The pattern matching is closely designed to ServeMux in net/http package of Go programming language. <PATTERN> consists of path, host + path or just host. The path must start with "/". If it ends with "/", it matches all request path in its subtree. To deal with the request to the directory without trailing slash, the path which ends with "/" also matches the request path which only lacks trailing '/' (e.g., path "/foo/" matches request path "/foo"). If it does not end with "/", it performs exact match against the request path. If host is given, it performs a match against the request host. For a request received on the frontend listener with "sni-fwd" parameter enabled, SNI host is used instead of a request host. If host alone is given, "/" is appended to it, so that it matches all request paths under the host (e.g., specifying "nghttp2.org" equals to "nghttp2.org/"). CONNECT method is treated specially. It does not have path, and we don't allow empty path. To workaround this, we assume that CONNECT method has "/" as path.

    Patterns with host take precedence over patterns with just path. Then, longer patterns take precedence over shorter ones.

    Host can include "*" in the left most position to indicate wildcard match (only suffix match is done). The "*" must match at least one character. For example, host pattern "*.nghttp2.org" matches against "www.nghttp2.org" and "git.ngttp2.org", but does not match against "nghttp2.org". The exact hosts match takes precedence over the wildcard hosts match.

    If path part ends with "*", it is treated as wildcard path. The wildcard path behaves differently from the normal path. For normal path, match is made around the boundary of path component separator,"/". On the other hand, the wildcard path does not take into account the path component separator. All paths which include the wildcard path without last "*" as prefix, and are strictly longer than wildcard path without last "*" are matched. "*" must match at least one character. For example, the pattern "/foo*" matches "/foo/" and "/foobar". But it does not match "/foo", or "/fo".

    If <PATTERN> is omitted or empty string, "/" is used as pattern, which matches all request paths (catch-all pattern). The catch-all backend must be given.

    When doing a match, nghttpx made some normalization to pattern, request host and path. For host part, they are converted to lower case. For path part, percent-encoded unreserved characters defined in RFC 3986 are decoded, and any dot-segments (".." and ".") are resolved and removed.

    For example, -b'127.0.0.1,8080;nghttp2.org/httpbin/' matches the request host "nghttp2.org" and the request path "/httpbin/get", but does not match the request host "nghttp2.org" and the request path "/index.html".

    The multiple <PATTERN>s can be specified, delimiting them by ":". Specifying -b'127.0.0.1,8080;nghttp2.org:www.nghttp2.org' has the same effect to specify -b'127.0.0.1,8080;nghttp2.org' and -b'127.0.0.1,8080;www.nghttp2.org'.

    The backend addresses sharing same <PATTERN> are grouped together forming load balancing group.

    Several parameters <PARAM> are accepted after <PATTERN>. The parameters are delimited by ";". The available parameters are: "proto=<PROTO>", "tls", "sni=<SNI_HOST>", "fall=<N>", "rise=<N>", "affinity=<METHOD>", "dns", "redirect-if-not-tls", "upgrade-scheme", "mruby=<PATH>", "read-timeout=<DURATION>", "write-timeout=<DURATION>", "group=<GROUP>", "group-weight=<N>", "weight=<N>", and "dnf". The parameter consists of keyword, and optionally followed by "=" and value. For example, the parameter "proto=h2" consists of the keyword "proto" and value "h2". The parameter "tls" consists of the keyword "tls" without value. Each parameter is described as follows.

    The backend application protocol can be specified using optional "proto" parameter, and in the form of "proto=<PROTO>". <PROTO> should be one of the following list without quotes: "h2", "http/1.1". The default value of <PROTO> is "http/1.1". Note that usually "h2" refers to HTTP/2 over TLS. But in this option, it may mean HTTP/2 over cleartext TCP unless "tls" keyword is used (see below).

    TLS can be enabled by specifying optional "tls" parameter. TLS is not enabled by default.

    With "sni=<SNI_HOST>" parameter, it can override the TLS SNI field value with given <SNI_HOST>. This will default to the backend <HOST> name

    The feature to detect whether backend is online or offline can be enabled using optional "fall" and "rise" parameters. Using "fall=<N>" parameter, if nghttpx cannot connect to a this backend <N> times in a row, this backend is assumed to be offline, and it is excluded from load balancing. If <N> is 0, this backend never be excluded from load balancing whatever times nghttpx cannot connect to it, and this is the default. There is also "rise=<N>" parameter. After backend was excluded from load balancing group, nghttpx periodically attempts to make a connection to the failed backend, and if the connection is made successfully <N> times in a row, the backend is assumed to be online, and it is now eligible for load balancing target. If <N> is 0, a backend is permanently offline, once it goes in that state, and this is the default behaviour.

    The session affinity is enabled using "affinity=<METHOD>" parameter. If "ip" is given in <METHOD>, client IP based session affinity is enabled. If "cookie" is given in <METHOD>, cookie based session affinity is enabled. If "none" is given in <METHOD>, session affinity is disabled, and this is the default. The session affinity is enabled per <PATTERN>. If at least one backend has "affinity" parameter, and its <METHOD> is not "none", session affinity is enabled for all backend servers sharing the same <PATTERN>. It is advised to set "affinity" parameter to all backend explicitly if session affinity is desired. The session affinity may break if one of the backend gets unreachable, or backend settings are reloaded or replaced by API.

    If "affinity=cookie" is used, the additional configuration is required. "affinity-cookie-name=<NAME>" must be used to specify a name of cookie to use. Optionally, "affinity-cookie-path=<PATH>" can be used to specify a path which cookie is applied. The optional "affinity-cookie-secure=<SECURE>" controls the Secure attribute of a cookie. The default value is "auto", and the Secure attribute is determined by a request scheme. If a request scheme is "https", then Secure attribute is set. Otherwise, it is not set. If <SECURE> is "yes", the Secure attribute is always set. If <SECURE> is "no", the Secure attribute is always omitted. "affinity-cookie-stickiness=<STICKINESS>" controls stickiness of this affinity. If <STICKINESS> is "loose", removing or adding a backend server might break the affinity and the request might be forwarded to a different backend server. If <STICKINESS> is "strict", removing the designated backend server breaks affinity, but adding new backend server does not cause breakage. If the designated backend server becomes unavailable, new backend server is chosen as if the request does not have an affinity cookie. <STICKINESS> defaults to "loose".

    By default, name resolution of backend host name is done at start up, or reloading configuration. If "dns" parameter is given, name resolution takes place dynamically. This is useful if backend address changes frequently. If "dns" is given, name resolution of backend host name at start up, or reloading configuration is skipped.

    If "redirect-if-not-tls" parameter is used, the matched backend requires that frontend connection is TLS encrypted. If it isn't, nghttpx responds to the request with 308 status code, and https URI the client should use instead is included in Location header field. The port number in redirect URI is 443 by default, and can be changed using --redirect-https-port option. If at least one backend has "redirect-if-not-tls" parameter, this feature is enabled for all backend servers sharing the same <PATTERN>. It is advised to set "redirect-if-no-tls" parameter to all backends explicitly if this feature is desired.

    If "upgrade-scheme" parameter is used along with "tls" parameter, HTTP/2 :scheme pseudo header field is changed to "https" from "http" when forwarding a request to this particular backend. This is a workaround for a backend server which requires "https" :scheme pseudo header field on TLS encrypted connection.

    "mruby=<PATH>" parameter specifies a path to mruby script file which is invoked when this pattern is matched. All backends which share the same pattern must have the same mruby path.

    "read-timeout=<DURATION>" and "write-timeout=<DURATION>" parameters specify the read and write timeout of the backend connection when this pattern is matched. All backends which share the same pattern must have the same timeouts. If these timeouts are entirely omitted for a pattern, --backend-read-timeout and --backend-write-timeout are used.

    "group=<GROUP>" parameter specifies the name of group this backend address belongs to. By default, it belongs to the unnamed default group. The name of group is unique per pattern. "group-weight=<N>" parameter specifies the weight of the group. The higher weight gets more frequently selected by the load balancing algorithm. <N> must be [1, 256] inclusive. The weight 8 has 4 times more weight than 2. <N> must be the same for all addresses which share the same <GROUP>. If "group-weight" is omitted in an address, but the other address which belongs to the same group specifies "group-weight", its weight is used. If no "group-weight" is specified for all addresses, the weight of a group becomes 1. "group" and "group-weight" are ignored if session affinity is enabled.

    "weight=<N>" parameter specifies the weight of the backend address inside a group which this address belongs to. The higher weight gets more frequently selected by the load balancing algorithm. <N> must be [1, 256] inclusive. The weight 8 has 4 times more weight than weight 2. If this parameter is omitted, weight becomes 1. "weight" is ignored if session affinity is enabled.

    If "dnf" parameter is specified, an incoming request is not forwarded to a backend and just consumed along with the request body (actually a backend server never be contacted). It is expected that the HTTP response is generated by mruby script (see "mruby=<PATH>" parameter above). "dnf" is an abbreviation of "do not forward".

    Since ";" and ":" are used as delimiter, <PATTERN> must not contain these characters. In order to include ":" in <PATTERN>, one has to specify "%3A" (which is percent-encoded from of ":") instead. Since ";" has special meaning in shell, the option value must be quoted.

    Default: 127.0.0.1,80

-f, --frontend=(<HOST>,<PORT>|unix:<PATH>)[[;<PARAM>]...]
    Set frontend host and port. If <HOST> is '*', it assumes all addresses including both IPv4 and IPv6. UNIX domain socket can be specified by prefixing path name with "unix:" (e.g., unix:/var/run/nghttpx.sock). This option can be used multiple times to listen to multiple addresses.

    This option can take 0 or more parameters, which are described below. Note that "api" and "healthmon" parameters are mutually exclusive.

    Optionally, TLS can be disabled by specifying "no-tls" parameter. TLS is enabled by default.

    If "sni-fwd" parameter is used, when performing a match to select a backend server, SNI host name received from the client is used instead of the request host. See --backend option about the pattern match.

    To make this frontend as API endpoint, specify "api" parameter. This is disabled by default. It is important to limit the access to the API frontend. Otherwise, someone may change the backend server, and break your services, or expose confidential information to the outside the world.

    To make this frontend as health monitor endpoint, specify "healthmon" parameter. This is disabled by default. Any requests which come through this address are replied with 200 HTTP status, without no body.

    To accept PROXY protocol version 1 and 2 on frontend connection, specify "proxyproto" parameter. This is disabled by default.

    To receive HTTP/3 (QUIC) traffic, specify "quic" parameter. It makes nghttpx listen on UDP port rather than TCP port. UNIX domain socket, "api", and "healthmon" parameters cannot be used with "quic" parameter.

    Default: *,3000

--backlog=<N>
    Set listen backlog size.

    Default: 65536

--backend-address-family=(auto|IPv4|IPv6)
    Specify address family of backend connections. If "auto" is given, both IPv4 and IPv6 are considered. If "IPv4" is given, only IPv4 address is considered. If "IPv6" is given, only IPv6 address is considered.

    Default: auto

--backend-http-proxy-uri=<URI>
    Specify proxy URI in the form http://[<USER>:<PASS>@]<PROXY>:<PORT>. If a proxy requires authentication, specify <USER> and <PASS>. Note that they must be properly percent-encoded. This proxy is used when the backend connection is HTTP/2. First, make a CONNECT request to the proxy and it connects to the backend on behalf of nghttpx. This forms tunnel. After that, nghttpx performs SSL/TLS handshake with the downstream through the tunnel. The timeouts when connecting and making CONNECT request can be specified by --backend-read-timeout and --backend-write-timeout options.

  Performance

-n, --workers=<N>
    Set the number of worker threads.

    Default: 1

--single-thread
    Run everything in one thread inside the worker process. This feature is provided for better debugging experience, or for the platforms which lack thread support. If threading is disabled, this option is always enabled.

--read-rate=<SIZE>
    Set maximum average read rate on frontend connection. Setting 0 to this option means read rate is unlimited.

    Default: 0

--read-burst=<SIZE>
    Set maximum read burst size on frontend connection. Setting 0 to this option means read burst size is unlimited.

    Default: 0

--write-rate=<SIZE>
    Set maximum average write rate on frontend connection. Setting 0 to this option means write rate is unlimited.

    Default: 0

--write-burst=<SIZE>
    Set maximum write burst size on frontend connection. Setting 0 to this option means write burst size is unlimited.

    Default: 0

--worker-read-rate=<SIZE>
    Set maximum average read rate on frontend connection per worker. Setting 0 to this option means read rate is unlimited. Not implemented yet.

    Default: 0

--worker-read-burst=<SIZE>
    Set maximum read burst size on frontend connection per worker. Setting 0 to this option means read burst size is unlimited. Not implemented yet.

    Default: 0

--worker-write-rate=<SIZE>
    Set maximum average write rate on frontend connection per worker. Setting 0 to this option means write rate is unlimited. Not implemented yet.

    Default: 0

--worker-write-burst=<SIZE>
    Set maximum write burst size on frontend connection per worker. Setting 0 to this option means write burst size is unlimited. Not implemented yet.

    Default: 0

--worker-frontend-connections=<N>
    Set maximum number of simultaneous connections frontend accepts. Setting 0 means unlimited.

    Default: 0

--backend-connections-per-host=<N>
    Set maximum number of backend concurrent connections (and/or streams in case of HTTP/2) per origin host. This option is meaningful when --http2-proxy option is used. The origin host is determined by authority portion of request URI (or :authority header field for HTTP/2). To limit the number of connections per frontend for default mode, use --backend-connections-per-frontend.

    Default: 8

--backend-connections-per-frontend=<N>
    Set maximum number of backend concurrent connections (and/or streams in case of HTTP/2) per frontend. This option is only used for default mode. 0 means unlimited. To limit the number of connections per host with --http2-proxy option, use --backend-connections-per-host.

    Default: 0

--rlimit-nofile=<N>
    Set maximum number of open files (RLIMIT_NOFILE) to <N>. If 0 is given, nghttpx does not set the limit.

    Default: 0

--rlimit-memlock=<N>
    Set maximum number of bytes of memory that may be locked into RAM. If 0 is given, nghttpx does not set the limit.

    Default: 0

--backend-request-buffer=<SIZE>
    Set buffer size used to store backend request.

    Default: 16K

--backend-response-buffer=<SIZE>
    Set buffer size used to store backend response.

    Default: 128K

--fastopen=<N>
    Enables "TCP Fast Open" for the listening socket and limits the maximum length for the queue of connections that have not yet completed the three-way handshake. If value is 0 then fast open is disabled.

    Default: 0

--no-kqueue
    Don't use kqueue. This option is only applicable for the platforms which have kqueue. For other platforms, this option will be simply ignored.

  Timeout

--frontend-http2-idle-timeout=<DURATION>
    Specify idle timeout for HTTP/2 frontend connection. If no active streams exist for this duration, connection is closed.

    Default: 3m

--frontend-http3-idle-timeout=<DURATION>
    Specify idle timeout for HTTP/3 frontend connection. If no active streams exist for this duration, connection is closed.

    Default: 3m

--frontend-write-timeout=<DURATION>
    Specify write timeout for all frontend connections.

    Default: 30s

--frontend-keep-alive-timeout=<DURATION>
    Specify keep-alive timeout for frontend HTTP/1 connection.

    Default: 1m

--frontend-header-timeout=<DURATION>
    Specify duration that the server waits for an HTTP request header fields to be received completely. On timeout, HTTP/1 and HTTP/2 connections are closed. For HTTP/3, the stream is shutdown, and the connection itself is left intact.

    Default: 1m

--stream-read-timeout=<DURATION>
    Specify read timeout for HTTP/2 streams. 0 means no timeout.

    Default: 0

--stream-write-timeout=<DURATION>
    Specify write timeout for HTTP/2 streams. 0 means no timeout.

    Default: 1m

--backend-read-timeout=<DURATION>
    Specify read timeout for backend connection.

    Default: 1m

--backend-write-timeout=<DURATION>
    Specify write timeout for backend connection.

    Default: 30s

--backend-connect-timeout=<DURATION>
    Specify timeout before establishing TCP connection to backend.

    Default: 30s

--backend-keep-alive-timeout=<DURATION>
    Specify keep-alive timeout for backend HTTP/1 connection.

    Default: 2s

--listener-disable-timeout=<DURATION>
    After accepting connection failed, connection listener is disabled for a given amount of time. Specifying 0 disables this feature.

    Default: 30s

--frontend-http2-setting-timeout=<DURATION>
    Specify timeout before SETTINGS ACK is received from client.

    Default: 10s

--backend-http2-settings-timeout=<DURATION>
    Specify timeout before SETTINGS ACK is received from backend server.

    Default: 10s

--backend-max-backoff=<DURATION>
    Specify maximum backoff interval. This is used when doing health check against offline backend (see "fail" parameter in --backend option). It is also used to limit the maximum interval to temporarily disable backend when nghttpx failed to connect to it. These intervals are calculated using exponential backoff, and consecutive failed attempts increase the interval. This option caps its maximum value.

    Default: 2m

  SSL/TLS

--ciphers=<SUITE>
    Set allowed cipher list for frontend connection. The format of the string is described in OpenSSL ciphers(1). This option sets cipher suites for TLSv1.2 or earlier. Use --tls13-ciphers for TLSv1.3.

    Default: ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384

--tls13-ciphers=<SUITE>
    Set allowed cipher list for frontend connection. The format of the string is described in OpenSSL ciphers(1). This option sets cipher suites for TLSv1.3. Use --ciphers for TLSv1.2 or earlier.

    Default: TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256

--client-ciphers=<SUITE>
    Set allowed cipher list for backend connection. The format of the string is described in OpenSSL ciphers(1). This option sets cipher suites for TLSv1.2 or earlier. Use --tls13-client-ciphers for TLSv1.3.

    Default: ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384

--tls13-client-ciphers=<SUITE>
    Set allowed cipher list for backend connection. The format of the string is described in OpenSSL ciphers(1). This option sets cipher suites for TLSv1.3. Use --tls13-client-ciphers for TLSv1.2 or earlier.

    Default: TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256

--ecdh-curves=<LIST>
    Set supported curve list for frontend connections. <LIST> is a colon separated list of curve NID or names in the preference order. The supported curves depend on the linked OpenSSL library. This function requires OpenSSL >= 1.0.2.

    Default: X25519:P-256:P-384:P-521

-k, --insecure
    Don't verify backend server's certificate if TLS is enabled for backend connections.

--cacert=<PATH>
    Set path to trusted CA certificate file. It is used in backend TLS connections to verify peer's certificate. It is also used to verify OCSP response from the script set by --fetch-ocsp-response-file. The file must be in PEM format. It can contain multiple certificates. If the linked OpenSSL is configured to load system wide certificates, they are loaded at startup regardless of this option.

--private-key-passwd-file=<PATH>
    Path to file that contains password for the server's private key. If none is given and the private key is password protected it'll be requested interactively.

--subcert=<KEYPATH>:<CERTPATH>[[;<PARAM>]...]
    Specify additional certificate and private key file. nghttpx will choose certificates based on the hostname indicated by client using TLS SNI extension. If nghttpx is built with OpenSSL >= 1.0.2, the shared elliptic curves (e.g., P-256) between client and server are also taken into consideration. This allows nghttpx to send ECDSA certificate to modern clients, while sending RSA based certificate to older clients. This option can be used multiple times. To make OCSP stapling work, <CERTPATH> must be absolute path.

    Additional parameter can be specified in <PARAM>. The available <PARAM> is "sct-dir=<DIR>".

    "sct-dir=<DIR>" specifies the path to directory which contains *.sct files for TLS signed_certificate_timestamp extension (RFC 6962). This feature requires OpenSSL >= 1.0.2. See also --tls-sct-dir option.

--dh-param-file=<PATH>
    Path to file that contains DH parameters in PEM format. Without this option, DHE cipher suites are not available.

--alpn-list=<LIST>
    Comma delimited list of ALPN protocol identifier sorted in the order of preference. That means most desirable protocol comes first. The parameter must be delimited by a single comma only and any white spaces are treated as a part of protocol string.

    Default: h2,h2-16,h2-14,http/1.1

--verify-client
    Require and verify client certificate.

--verify-client-cacert=<PATH>
    Path to file that contains CA certificates to verify client certificate. The file must be in PEM format. It can contain multiple certificates.

--verify-client-tolerate-expired
    Accept expired client certificate. Operator should handle the expired client certificate by some means (e.g., mruby script). Otherwise, this option might cause a security risk.

--client-private-key-file=<PATH>
    Path to file that contains client private key used in backend client authentication.

--client-cert-file=<PATH>
    Path to file that contains client certificate used in backend client authentication.

--tls-min-proto-version=<VER>
    Specify minimum SSL/TLS protocol. The name matching is done in case-insensitive manner. The versions between --tls-min-proto-version and --tls-max-proto-version are enabled. If the protocol list advertised by client does not overlap this range, you will receive the error message "unknown protocol". If a protocol version lower than TLSv1.2 is specified, make sure that the compatible ciphers are included in --ciphers option. The default cipher list only includes ciphers compatible with TLSv1.2 or above. The available versions are: TLSv1.3, TLSv1.2, TLSv1.1, and TLSv1.0

    Default: TLSv1.2

--tls-max-proto-version=<VER>
    Specify maximum SSL/TLS protocol. The name matching is done in case-insensitive manner. The versions between --tls-min-proto-version and --tls-max-proto-version are enabled. If the protocol list advertised by client does not overlap this range, you will receive the error message "unknown protocol". The available versions are: TLSv1.3, TLSv1.2, TLSv1.1, and TLSv1.0

    Default: TLSv1.3

--tls-ticket-key-file=<PATH>
    Path to file that contains random data to construct TLS session ticket parameters. If aes-128-cbc is given in --tls-ticket-key-cipher, the file must contain exactly 48 bytes. If aes-256-cbc is given in --tls-ticket-key-cipher, the file must contain exactly 80 bytes. This options can be used repeatedly to specify multiple ticket parameters. If several files are given, only the first key is used to encrypt TLS session tickets. Other keys are accepted but server will issue new session ticket with first key. This allows session key rotation. Please note that key rotation does not occur automatically. User should rearrange files or change options values and restart nghttpx gracefully. If opening or reading given file fails, all loaded keys are discarded and it is treated as if none of this option is given. If this option is not given or an error occurred while opening or reading a file, key is generated every 1 hour internally and they are valid for 12 hours. This is recommended if ticket key sharing between nghttpx instances is not required.

--tls-ticket-key-memcached=<HOST>,<PORT>[;tls]
    Specify address of memcached server to get TLS ticket keys for session resumption. This enables shared TLS ticket key between multiple nghttpx instances. nghttpx does not set TLS ticket key to memcached. The external ticket key generator is required. nghttpx just gets TLS ticket keys from memcached, and use them, possibly replacing current set of keys. It is up to extern TLS ticket key generator to rotate keys frequently. See "TLS SESSION TICKET RESUMPTION" section in manual page to know the data format in memcached entry. Optionally, memcached connection can be encrypted with TLS by specifying "tls" parameter.

--tls-ticket-key-memcached-address-family=(auto|IPv4|IPv6)
    Specify address family of memcached connections to get TLS ticket keys. If "auto" is given, both IPv4 and IPv6 are considered. If "IPv4" is given, only IPv4 address is considered. If "IPv6" is given, only IPv6 address is considered.

    Default: auto

--tls-ticket-key-memcached-interval=<DURATION>
    Set interval to get TLS ticket keys from memcached.

    Default: 10m

--tls-ticket-key-memcached-max-retry=<N>
    Set maximum number of consecutive retries before abandoning TLS ticket key retrieval. If this number is reached, the attempt is considered as failure, and "failure" count is incremented by 1, which contributed to the value controlled --tls-ticket-key-memcached-max-fail option.

    Default: 3

--tls-ticket-key-memcached-max-fail=<N>
    Set maximum number of consecutive failure before disabling TLS ticket until next scheduled key retrieval.

    Default: 2

--tls-ticket-key-cipher=<CIPHER>
    Specify cipher to encrypt TLS session ticket. Specify either aes-128-cbc or aes-256-cbc. By default, aes-128-cbc is used.

--tls-ticket-key-memcached-cert-file=<PATH>
    Path to client certificate for memcached connections to get TLS ticket keys.

--tls-ticket-key-memcached-private-key-file=<PATH>
    Path to client private key for memcached connections to get TLS ticket keys.

--fetch-ocsp-response-file=<PATH>
    Path to fetch-ocsp-response script file. It should be absolute path.

    Default: /usr/local/share/nghttp2/fetch-ocsp-response

--ocsp-update-interval=<DURATION>
    Set interval to update OCSP response cache.

    Default: 4h

--ocsp-startup
    Start accepting connections after initial attempts to get OCSP responses finish. It does not matter some of the attempts fail. This feature is useful if OCSP responses must be available before accepting connections.

--no-verify-ocsp
    nghttpx does not verify OCSP response.

--no-ocsp
    Disable OCSP stapling.

--tls-session-cache-memcached=<HOST>,<PORT>[;tls]
    Specify address of memcached server to store session cache. This enables shared session cache between multiple nghttpx instances. Optionally, memcached connection can be encrypted with TLS by specifying "tls" parameter.

--tls-session-cache-memcached-address-family=(auto|IPv4|IPv6)
    Specify address family of memcached connections to store session cache. If "auto" is given, both IPv4 and IPv6 are considered. If "IPv4" is given, only IPv4 address is considered. If "IPv6" is given, only IPv6 address is considered.

    Default: auto

--tls-session-cache-memcached-cert-file=<PATH>
    Path to client certificate for memcached connections to store session cache.

--tls-session-cache-memcached-private-key-file=<PATH>
    Path to client private key for memcached connections to store session cache.

--tls-dyn-rec-warmup-threshold=<SIZE>
    Specify the threshold size for TLS dynamic record size behaviour. During a TLS session, after the threshold number of bytes have been written, the TLS record size will be increased to the maximum allowed (16K). The max record size will continue to be used on the active TLS session. After --tls-dyn-rec-idle-timeout has elapsed, the record size is reduced to 1300 bytes. Specify 0 to always use the maximum record size, regardless of idle period. This behaviour applies to all TLS based frontends, and TLS HTTP/2 backends.

    Default: 1M

--tls-dyn-rec-idle-timeout=<DURATION>
    Specify TLS dynamic record size behaviour timeout. See --tls-dyn-rec-warmup-threshold for more information. This behaviour applies to all TLS based frontends, and TLS HTTP/2 backends.

    Default: 1s

--no-http2-cipher-block-list
    Allow block listed cipher suite on frontend HTTP/2 connection. See https://tools.ietf.org/html/rfc7540#appendix-A for the complete HTTP/2 cipher suites block list.

--client-no-http2-cipher-block-list
    Allow block listed cipher suite on backend HTTP/2 connection. See https://tools.ietf.org/html/rfc7540#appendix-A for the complete HTTP/2 cipher suites block list.

--tls-sct-dir=<DIR>
    Specifies the directory where *.sct files exist. All *.sct files in <DIR> are read, and sent as extension_data of TLS signed_certificate_timestamp (RFC 6962) to client. These *.sct files are for the certificate specified in positional command-line argument <CERT>, or certificate option in configuration file. For additional certificates, use --subcert option. This option requires OpenSSL >= 1.0.2.

--psk-secrets=<PATH>
    Read list of PSK identity and secrets from <PATH>. This is used for frontend connection. The each line of input file is formatted as <identity>:<hex-secret>, where <identity> is PSK identity, and <hex-secret> is secret in hex. An empty line, and line which starts with '#' are skipped. The default enabled cipher list might not contain any PSK cipher suite. In that case, desired PSK cipher suites must be enabled using --ciphers option. The desired PSK cipher suite may be block listed by HTTP/2. To use those cipher suites with HTTP/2, consider to use --no-http2-cipher-block-list option. But be aware its implications.

--client-psk-secrets=<PATH>
    Read PSK identity and secrets from <PATH>. This is used for backend connection. The each line of input file is formatted as <identity>:<hex-secret>, where <identity> is PSK identity, and <hex-secret> is secret in hex. An empty line, and line which starts with '#' are skipped. The first identity and secret pair encountered is used. The default enabled cipher list might not contain any PSK cipher suite. In that case, desired PSK cipher suites must be enabled using --client-ciphers option. The desired PSK cipher suite may be block listed by HTTP/2. To use those cipher suites with HTTP/2, consider to use --client-no-http2-cipher-block-list option. But be aware its implications.

--tls-no-postpone-early-data
    By default, except for QUIC connections, nghttpx postpones forwarding HTTP requests sent in early data, including those sent in partially in it, until TLS handshake finishes. If all backend server recognizes "Early-Data" header field, using this option makes nghttpx not postpone forwarding request and get full potential of 0-RTT data.

--tls-max-early-data=<SIZE>
    Sets the maximum amount of 0-RTT data that server accepts.

    Default: 16K

--tls-ktls
    Enable ktls. For server, ktls is enable if --tls-session-cache-memcached is not configured.

  HTTP/2

-c, --frontend-http2-max-concurrent-streams=<N>
    Set the maximum number of the concurrent streams in one frontend HTTP/2 session.

    Default: 100

--backend-http2-max-concurrent-streams=<N>
    Set the maximum number of the concurrent streams in one backend HTTP/2 session. This sets maximum number of concurrent opened pushed streams. The maximum number of concurrent requests are set by a remote server.

    Default: 100

--frontend-http2-window-size=<SIZE>
    Sets the per-stream initial window size of HTTP/2 frontend connection.

    Default: 65535

--frontend-http2-connection-window-size=<SIZE>
    Sets the per-connection window size of HTTP/2 frontend connection.

    Default: 65535

--backend-http2-window-size=<SIZE>
    Sets the initial window size of HTTP/2 backend connection.

    Default: 65535

--backend-http2-connection-window-size=<SIZE>
    Sets the per-connection window size of HTTP/2 backend connection.

    Default: 2147483647

--http2-no-cookie-crumbling
    Don't crumble cookie header field.

--padding=<N>
    Add at most <N> bytes to a HTTP/2 frame payload as padding. Specify 0 to disable padding. This option is meant for debugging purpose and not intended to enhance protocol security.

--no-server-push
    Disable HTTP/2 server push. Server push is supported by default mode and HTTP/2 frontend via Link header field. It is also supported if both frontend and backend are HTTP/2 in default mode. In this case, server push from backend session is relayed to frontend, and server push via Link header field is also supported.

--frontend-http2-optimize-write-buffer-size
    (Experimental) Enable write buffer size optimization in frontend HTTP/2 TLS connection. This optimization aims to reduce write buffer size so that it only contains bytes which can send immediately. This makes server more responsive to prioritized HTTP/2 stream because the buffering of lower priority stream is reduced. This option is only effective on recent Linux platform.

--frontend-http2-optimize-window-size
    (Experimental) Automatically tune connection level window size of frontend HTTP/2 TLS connection. If this feature is enabled, connection window size starts with the default window size, 65535 bytes. nghttpx automatically adjusts connection window size based on TCP receiving window size. The maximum window size is capped by the value specified by --frontend-http2-connection-window-size. Since the stream is subject to stream level window size, it should be adjusted using --frontend-http2-window-size option as well. This option is only effective on recent Linux platform.

--frontend-http2-encoder-dynamic-table-size=<SIZE>
    Specify the maximum dynamic table size of HPACK encoder in the frontend HTTP/2 connection. The decoder (client) specifies the maximum dynamic table size it accepts. Then the negotiated dynamic table size is the minimum of this option value and the value which client specified.

    Default: 4K

--frontend-http2-decoder-dynamic-table-size=<SIZE>
    Specify the maximum dynamic table size of HPACK decoder in the frontend HTTP/2 connection.

    Default: 4K

--backend-http2-encoder-dynamic-table-size=<SIZE>
    Specify the maximum dynamic table size of HPACK encoder in the backend HTTP/2 connection. The decoder (backend) specifies the maximum dynamic table size it accepts. Then the negotiated dynamic table size is the minimum of this option value and the value which backend specified.

    Default: 4K

--backend-http2-decoder-dynamic-table-size=<SIZE>
    Specify the maximum dynamic table size of HPACK decoder in the backend HTTP/2 connection.

    Default: 4K

  Mode

(default mode)
    Accept HTTP/2, and HTTP/1.1 over SSL/TLS. "no-tls" parameter is used in --frontend option, accept HTTP/2 and HTTP/1.1 over cleartext TCP. The incoming HTTP/1.1 connection can be upgraded to HTTP/2 through HTTP Upgrade.

-s, --http2-proxy
    Like default mode, but enable forward proxy. This is so called HTTP/2 proxy mode.

  Logging

-L, --log-level=<LEVEL>
    Set the severity level of log output. <LEVEL> must be one of INFO, NOTICE, WARN, ERROR and FATAL.

    Default: NOTICE

--accesslog-file=<PATH>
    Set path to write access log. To reopen file, send USR1 signal to nghttpx.

--accesslog-syslog
    Send access log to syslog. If this option is used, --accesslog-file option is ignored.

--accesslog-format=<FORMAT>
    Specify format string for access log. The default format is combined format. The following variables are available:

•   $remote_addr: client IP address.

•   $time_local: local time in Common Log format.

•   $time_iso8601: local time in ISO 8601 format.

•   $request: HTTP request line.

•   $status: HTTP response status code.

•   $body_bytes_sent: the number of bytes sent to client as response body.

•   $http_<VAR>: value of HTTP request header <VAR> where '_' in <VAR> is replaced with '-'.

•   $remote_port: client port.

•   $server_port: server port.

•   $request_time: request processing time in seconds with milliseconds resolution.

•   $pid: PID of the running process.

•   $alpn: ALPN identifier of the protocol which generates the response. For HTTP/1, ALPN is always http/1.1, regardless of minor version.

•   $tls_cipher: cipher used for SSL/TLS connection.

•   $tls_client_fingerprint_sha256: SHA-256 fingerprint of client certificate.

•   $tls_client_fingerprint_sha1: SHA-1 fingerprint of client certificate.

•   $tls_client_subject_name: subject name in client certificate.

•   $tls_client_issuer_name: issuer name in client certificate.

•   $tls_client_serial: serial number in client certificate.

•   $tls_protocol: protocol for SSL/TLS connection.

•   $tls_session_id: session ID for SSL/TLS connection.

•   $tls_session_reused: "r" if SSL/TLS session was reused. Otherwise, "."

•   $tls_sni: SNI server name for SSL/TLS connection.

•   $backend_host: backend host used to fulfill the request. "-" if backend host is not available.

•   $backend_port: backend port used to fulfill the request. "-" if backend host is not available.

•   $method: HTTP method

•   $path: Request path including query. For CONNECT request, authority is recorded.

•   $path_without_query: $path up to the first '?' character. For CONNECT request, authority is recorded.

•   $protocol_version: HTTP version (e.g., HTTP/1.1, HTTP/2)

    The variable can be enclosed by "{" and "}" for disambiguation (e.g., ${remote_addr}).

    Default: $remote_addr - - [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent"

--accesslog-write-early
    Write access log when response header fields are received from backend rather than when request transaction finishes.

--errorlog-file=<PATH>
    Set path to write error log. To reopen file, send USR1 signal to nghttpx. stderr will be redirected to the error log file unless --errorlog-syslog is used.

    Default: /dev/stderr

--errorlog-syslog
    Send error log to syslog. If this option is used, --errorlog-file option is ignored.

--syslog-facility=<FACILITY>
    Set syslog facility to <FACILITY>.

    Default: daemon

  HTTP

--add-x-forwarded-for
    Append X-Forwarded-For header field to the downstream request.

--strip-incoming-x-forwarded-for
    Strip X-Forwarded-For header field from inbound client requests.

--no-add-x-forwarded-proto
    Don't append additional X-Forwarded-Proto header field to the backend request. If inbound client sets X-Forwarded-Proto, and --no-strip-incoming-x-forwarded-proto option is used, they are passed to the backend.

--no-strip-incoming-x-forwarded-proto
    Don't strip X-Forwarded-Proto header field from inbound client requests.

--add-forwarded=<LIST>
    Append RFC 7239 Forwarded header field with parameters specified in comma delimited list <LIST>. The supported parameters are "by", "for", "host", and "proto". By default, the value of "by" and "for" parameters are obfuscated string. See --forwarded-by and --forwarded-for options respectively. Note that nghttpx does not translate non-standard X-Forwarded-* header fields into Forwarded header field, and vice versa.

--strip-incoming-forwarded
    Strip Forwarded header field from inbound client requests.

--forwarded-by=(obfuscated|ip|<VALUE>)
    Specify the parameter value sent out with "by" parameter of Forwarded header field. If "obfuscated" is given, the string is randomly generated at startup. If "ip" is given, the interface address of the connection, including port number, is sent with "by" parameter. In case of UNIX domain socket, "localhost" is used instead of address and port. User can also specify the static obfuscated string. The limitation is that it must start with "_", and only consists of character set [A-Za-z0-9._-], as described in RFC 7239.

    Default: obfuscated

--forwarded-for=(obfuscated|ip)
    Specify the parameter value sent out with "for" parameter of Forwarded header field. If "obfuscated" is given, the string is randomly generated for each client connection. If "ip" is given, the remote client address of the connection, without port number, is sent with "for" parameter. In case of UNIX domain socket, "localhost" is used instead of address.

    Default: obfuscated

--no-via
    Don't append to Via header field. If Via header field is received, it is left unaltered.

--no-strip-incoming-early-data
    Don't strip Early-Data header field from inbound client requests.

--no-location-rewrite
    Don't rewrite location header field in default mode. When --http2-proxy is used, location header field will not be altered regardless of this option.

--host-rewrite
    Rewrite host and :authority header fields in default mode. When --http2-proxy is used, these headers will not be altered regardless of this option.

--altsvc=<PROTOID,PORT[,HOST,[ORIGIN[,PARAMS]]]>
    Specify protocol ID, port, host and origin of alternative service. <HOST>, <ORIGIN> and <PARAMS> are optional. Empty <HOST> and <ORIGIN> are allowed and they are treated as nothing is specified. They are advertised in alt-svc header field only in HTTP/1.1 frontend. This option can be used multiple times to specify multiple alternative services. Example: --altsvc="h2,443,,,ma=3600; persist=1"

--http2-altsvc=<PROTOID,PORT[,HOST,[ORIGIN[,PARAMS]]]>
    Just like --altsvc option, but this altsvc is only sent in HTTP/2 frontend.

--add-request-header=<HEADER>
    Specify additional header field to add to request header set. The field name must be lowercase. This option just appends header field and won't replace anything already set. This option can be used several times to specify multiple header fields. Example: --add-request-header="foo: bar"

--add-response-header=<HEADER>
    Specify additional header field to add to response header set. The field name must be lowercase. This option just appends header field and won't replace anything already set. This option can be used several times to specify multiple header fields. Example: --add-response-header="foo: bar"

--request-header-field-buffer=<SIZE>
    Set maximum buffer size for incoming HTTP request header field list. This is the sum of header name and value in bytes. If trailer fields exist, they are counted towards this number.

    Default: 64K

--max-request-header-fields=<N>
    Set maximum number of incoming HTTP request header fields. If trailer fields exist, they are counted towards this number.

    Default: 100

--response-header-field-buffer=<SIZE>
    Set maximum buffer size for incoming HTTP response header field list. This is the sum of header name and value in bytes. If trailer fields exist, they are counted towards this number.

    Default: 64K

--max-response-header-fields=<N>
    Set maximum number of incoming HTTP response header fields. If trailer fields exist, they are counted towards this number.

    Default: 500

--error-page=(<CODE>|*)=<PATH>
    Set file path to custom error page served when nghttpx originally generates HTTP error status code <CODE>. <CODE> must be greater than or equal to 400, and at most 599. If "*" is used instead of <CODE>, it matches all HTTP status code. If error status code comes from backend server, the custom error pages are not used.

--server-name=<NAME>
    Change server response header field value to <NAME>.

    Default: nghttpx

--no-server-rewrite
    Don't rewrite server header field in default mode. When --http2-proxy is used, these headers will not be altered regardless of this option.

--redirect-https-port=<PORT>
    Specify the port number which appears in Location header field when redirect to HTTPS URI is made due to "redirect-if-not-tls" parameter in --backend option.

    Default: 443

--require-http-scheme
    Always require http or https scheme in HTTP request. It also requires that https scheme must be used for an encrypted connection. Otherwise, http scheme must be used. This option is recommended for a server deployment which directly faces clients and the services it provides only require http or https scheme.

  API

--api-max-request-body=<SIZE>
    Set the maximum size of request body for API request.

    Default: 32M

  DNS

--dns-cache-timeout=<DURATION>
    Set duration that cached DNS results remain valid. Note that nghttpx caches the unsuccessful results as well.

    Default: 10s

--dns-lookup-timeout=<DURATION>
    Set timeout that DNS server is given to respond to the initial DNS query. For the 2nd and later queries, server is given time based on this timeout, and it is scaled linearly.

    Default: 5s

--dns-max-try=<N>
    Set the number of DNS query before nghttpx gives up name lookup.

    Default: 2

--frontend-max-requests=<N>
    The number of requests that single frontend connection can process. For HTTP/2, this is the number of streams in one HTTP/2 connection. For HTTP/1, this is the number of keep alive requests. This is hint to nghttpx, and it may allow additional few requests. The default value is unlimited.

  Debug

--frontend-http2-dump-request-header=<PATH>
    Dumps request headers received by HTTP/2 frontend to the file denoted in <PATH>. The output is done in HTTP/1 header field format and each header block is followed by an empty line. This option is not thread safe and MUST NOT be used with option -n<N>, where <N> >= 2.

--frontend-http2-dump-response-header=<PATH>
    Dumps response headers sent from HTTP/2 frontend to the file denoted in <PATH>. The output is done in HTTP/1 header field format and each header block is followed by an empty line. This option is not thread safe and MUST NOT be used with option -n<N>, where <N> >= 2.

-o, --frontend-frame-debug
    Print HTTP/2 frames in frontend to stderr. This option is not thread safe and MUST NOT be used with option -n=N, where N >= 2.

  Process

-D, --daemon
    Run in a background. If -D is used, the current working directory is changed to '/'.

--pid-file=<PATH>
    Set path to save PID of this program.

--user=<USER>
    Run this program as <USER>. This option is intended to be used to drop root privileges.

--single-process
    Run this program in a single process mode for debugging purpose. Without this option, nghttpx creates at least 2 processes: main and worker processes. If this option is used, main and worker are unified into a single process. nghttpx still spawns additional process if neverbleed is used. In the single process mode, the signal handling feature is disabled.

--max-worker-processes=<N>
    The maximum number of worker processes. nghttpx spawns new worker process when it reloads its configuration. The previous worker process enters graceful termination period and will terminate when it finishes handling the existing connections. However, if reloading configurations happen very frequently, the worker processes might be piled up if they take a bit long time to finish the existing connections. With this option, if the number of worker processes exceeds the given value, the oldest worker process is terminated immediately. Specifying 0 means no limit and it is the default behaviour.

--worker-process-grace-shutdown-period=<DURATION>
    Maximum period for a worker process to terminate gracefully. When a worker process enters in graceful shutdown period (e.g., when nghttpx reloads its configuration) and it does not finish handling the existing connections in the given period of time, it is immediately terminated. Specifying 0 means no limit and it is the default behaviour.

  Scripting

--mruby-file=<PATH>
    Set mruby script file

--ignore-per-pattern-mruby-error
    Ignore mruby compile error for per-pattern mruby script file. If error occurred, it is treated as if no mruby file were specified for the pattern.

  HTTP/3 and QUIC

--frontend-quic-idle-timeout=<DURATION>
    Specify an idle timeout for QUIC connection.

    Default: 30s

--frontend-quic-debug-log
    Output QUIC debug log to /dev/stderr.

--quic-bpf-program-file=<PATH>
    Specify a path to eBPF program file reuseport_kern.o to direct an incoming QUIC UDP datagram to a correct socket.

    Default: /usr/local/lib/nghttp2/reuseport_kern.o

--frontend-quic-early-data
    Enable early data on frontend QUIC connections. nghttpx sends "Early-Data" header field to a backend server if a request is received in early data and handshake has not finished. All backend servers should deal with possibly replayed requests.

--frontend-quic-qlog-dir=<DIR>
    Specify a directory where a qlog file is written for frontend QUIC connections. A qlog file is created per each QUIC connection. The file name is ISO8601 basic format, followed by "-", server Source Connection ID and ".sqlog".

--frontend-quic-require-token
    Require an address validation token for a frontend QUIC connection. Server sends a token in Retry packet or NEW_TOKEN frame in the previous connection.

--frontend-quic-congestion-controller=<CC>
    Specify a congestion controller algorithm for a frontend QUIC connection. <CC> should be either "cubic" or "bbr".

    Default: cubic

--frontend-quic-secret-file=<PATH>
    Path to file that contains secure random data to be used as QUIC keying materials. It is used to derive keys for encrypting tokens and Connection IDs. It is not used to encrypt QUIC packets. Each line of this file must contain exactly 136 bytes hex-encoded string (when decoded the byte string is 68 bytes long). The first 3 bits of decoded byte string are used to identify the keying material. An empty line or a line which starts '#' is ignored. The file can contain more than one keying materials. Because the identifier is 3 bits, at most 8 keying materials are read and the remaining data is discarded. The first keying material in the file is primarily used for encryption and decryption for new connection. The other ones are used to decrypt data for the existing connections. Specifying multiple keying materials enables key rotation. Please note that key rotation does not occur automatically. User should update files or change options values and restart nghttpx gracefully. If opening or reading given file fails, all loaded keying materials are discarded and it is treated as if none of this option is given. If this option is not given or an error occurred while opening or reading a file, a keying material is generated internally on startup and reload.

--quic-server-id=<HEXSTRING>
    Specify server ID encoded in Connection ID to identify this particular server instance. Connection ID is encrypted and this part is not visible in public. It must be 4 bytes long and must be encoded in hex string (which is 8 bytes long). If this option is omitted, a random server ID is generated on startup and configuration reload.

--frontend-quic-initial-rtt=<DURATION>
    Specify the initial RTT of the frontend QUIC connection.

    Default: 333ms

--no-quic-bpf
    Disable eBPF.

--frontend-http3-window-size=<SIZE>
    Sets the per-stream initial window size of HTTP/3 frontend connection.

    Default: 256K

--frontend-http3-connection-window-size=<SIZE>
    Sets the per-connection window size of HTTP/3 frontend connection.

    Default: 1M

--frontend-http3-max-window-size=<SIZE>
    Sets the maximum per-stream window size of HTTP/3 frontend connection. The window size is adjusted based on the receiving rate of stream data. The initial value is the value specified by --frontend-http3-window-size and the window size grows up to <SIZE> bytes.

    Default: 6M

--frontend-http3-max-connection-window-size=<SIZE>
    Sets the maximum per-connection window size of HTTP/3 frontend connection. The window size is adjusted based on the receiving rate of stream data. The initial value is the value specified by --frontend-http3-connection-window-size and the window size grows up to <SIZE> bytes.

    Default: 8M

--frontend-http3-max-concurrent-streams=<N>
    Set the maximum number of the concurrent streams in one frontend HTTP/3 connection.

    Default: 100

  Misc

--conf=<PATH>
    Load configuration from <PATH>. Please note that nghttpx always tries to read the default configuration file if --conf is not given.

    Default: /etc/nghttpx/nghttpx.conf

--include=<PATH>
    Load additional configurations from <PATH>. File <PATH> is read when configuration parser encountered this option. This option can be used multiple times, or even recursively.

-v, --version
    Print version and exit.

-h, --help
    Print this help and exit.

    The <SIZE> argument is an integer and an optional unit (e.g., 10K is 10 * 1024). Units are K, M and G (powers of 1024).

    The <DURATION> argument is an integer and an optional unit (e.g., 1s is 1 second and 500ms is 500 milliseconds). Units are h, m, s or ms (hours, minutes, seconds and milliseconds, respectively). If a unit is omitted, a second is used as unit.

FILES

/etc/nghttpx/nghttpx.conf
    The default configuration file path nghttpx searches at startup. The configuration file path can be changed using --conf option.

    Those lines which are staring # are treated as comment.

    The option name in the configuration file is the long command-line option name with leading -- stripped (e.g., frontend). Put = between option name and value. Don't put extra leading or trailing spaces.

    When specifying arguments including characters which have special meaning to a shell, we usually use quotes so that shell does not interpret them. When writing this configuration file, quotes for this purpose must not be used. For example, specify additional request header field, do this:

    add-request-header=foo: bar

    instead of:

    add-request-header="foo: bar"

    The options which do not take argument in the command-line take argument in the configuration file. Specify yes as an argument (e.g., http2-proxy=yes). If other string is given, it is ignored.

    To specify private key and certificate file which are given as positional arguments in command-line, use private-key-file and certificate-file.

    --conf option cannot be used in the configuration file and will be ignored if specified.

Error log
    Error log is written to stderr by default. It can be configured using --errorlog-file. The format of log message is as follows:

    <datetime> <main-pid> <current-pid> <thread-id> <level> (<filename>:<line>) <msg>

<datetime>
    It is a combination of date and time when the log is written. It is in ISO 8601 format.

<main-pid>
    It is a main process ID.

<current-pid>
    It is a process ID which writes this log.

<thread-id>
    It is a thread ID which writes this log. It would be unique within <current-pid>.

<filename> and <line>
    They are source file name, and line number which produce this log.

<msg>
    It is a log message body.

SIGNALS

SIGQUIT
    Shutdown gracefully. First accept pending connections and stop accepting connection. After all connections are handled, nghttpx exits.

SIGHUP
    Reload configuration file given in --conf.

SIGUSR1
    Reopen log files.

    SIGUSR2 Fork and execute nghttpx. It will execute the binary in the same path with same command-line arguments and environment variables. As of nghttpx version 1.20.0, the new main process sends SIGQUIT to the original main process when it is ready to serve requests. For the earlier versions of nghttpx, user has to send SIGQUIT to the original main process.

    The difference between SIGUSR2 (+ SIGQUIT) and SIGHUP is that former is usually used to execute new binary, and the main process is newly spawned. On the other hand, the latter just reloads configuration file, and the same main process continues to exist.

    NOTE: nghttpx consists of multiple processes: one process for processing these signals, and another one for processing requests. The former spawns the latter. The former is called main process, and the latter is called worker process. If neverbleed is enabled, the worker process spawns neverbleed daemon process which does RSA key processing. The above signal must be sent to the main process. If the other processes received one of them, it is ignored. This behaviour of these processes may change in the future release. In other words, in the future release, the processes other than main process may terminate upon the reception of these signals. Therefore these signals should not be sent to the processes other than main process.

SERVER PUSH

nghttpx supports HTTP/2 server push in default mode with Link header field. nghttpx looks for Link header field (RFC 5988) in response headers from backend server and extracts URI-reference with parameter rel=preload (see preload) and pushes those URIs to the frontend client. Here is a sample Link header field to initiate server push:

Link: </fonts/font.woff>; rel=preload
Link: </css/theme.css>; rel=preload

Currently, the following restriction is applied for server push:

1.  The associated stream must have method "GET" or "POST". The associated stream's status code must be 200.

    This limitation may be loosened in the future release.

    nghttpx also supports server push if both frontend and backend are HTTP/2 in default mode. In this case, in addition to server push via Link header field, server push from backend is forwarded to frontend HTTP/2 session.

    HTTP/2 server push will be disabled if --http2-proxy is used.

UNIX DOMAIN SOCKET

nghttpx supports UNIX domain socket with a filename for both frontend and backend connections.

Please note that current nghttpx implementation does not delete a socket with a filename. And on start up, if nghttpx detects that the specified socket already exists in the file system, nghttpx first deletes it. However, if SIGUSR2 is used to execute new binary and both old and new configurations use same filename, new binary does not delete the socket and continues to use it.

OCSP STAPLING

OCSP query is done using external Python script fetch-ocsp-response, which has been originally developed in Perl as part of h2o project (https://github.com/h2o/h2o), and was translated into Python.

The script file is usually installed under $(prefix)/share/nghttp2/ directory. The actual path to script can be customized using --fetch-ocsp-response-file option.

If OCSP query is failed, previous OCSP response, if any, is continued to be used.

--fetch-ocsp-response-file option provides wide range of possibility to manage OCSP response. It can take an arbitrary script or executable. The requirement is that it supports the command-line interface of fetch-ocsp-response script, and it must return a valid DER encoded OCSP response on success. It must return exit code 0 on success, and 75 for temporary error, and the other error code for generic failure. For large cluster of servers, it is not efficient for each server to perform OCSP query using fetch-ocsp-response. Instead, you can retrieve OCSP response in some way, and store it in a disk or a shared database. Then specify a program in --fetch-ocsp-response-file to fetch it from those stores. This could provide a way to share the OCSP response between fleet of servers, and also any OCSP query strategy can be applied which may be beyond the ability of nghttpx itself or fetch-ocsp-response script.

TLS SESSION RESUMPTION

nghttpx supports TLS session resumption through both session ID and session ticket.

  SESSION ID RESUMPTION

By default, session ID is shared by all worker threads.

If --tls-session-cache-memcached is given, nghttpx will insert serialized session data to memcached with nghttpx:tls-session-cache: + lowercase hex string of session ID as a memcached entry key, with expiry time 12 hours. Session timeout is set to 12 hours.

By default, connections to memcached server are not encrypted. To enable encryption, use tls keyword in --tls-session-cache-memcached option.

  TLS SESSION TICKET RESUMPTION

By default, session ticket is shared by all worker threads. The automatic key rotation is also enabled by default. Every an hour, new encryption key is generated, and previous encryption key becomes decryption only key. We set session timeout to 12 hours, and thus we keep at most 12 keys.

If --tls-ticket-key-memcached is given, encryption keys are retrieved from memcached. nghttpx just reads keys from memcached; one has to deploy key generator program to update keys frequently (e.g., every 1 hour). The example key generator tlsticketupdate.go is available under contrib directory in nghttp2 archive. The memcached entry key is nghttpx:tls-ticket-key. The data format stored in memcached is the binary format described below:

+--------------+-------+----------------+
| VERSION (4)  |LEN (2)|KEY(48 or 80) ...
+--------------+-------+----------------+
               ^                        |
               |                        |
               +------------------------+
               (LEN, KEY) pair can be repeated

All numbers in the above figure is bytes. All integer fields are network byte order.

First 4 bytes integer VERSION field, which must be 1. The 2 bytes integer LEN field gives the length of following KEY field, which contains key. If --tls-ticket-key-cipher=aes-128-cbc is used, LEN must be 48. If --tls-ticket-key-cipher=aes-256-cbc is used, LEN must be 80. LEN and KEY pair can be repeated multiple times to store multiple keys. The key appeared first is used as encryption key. All the remaining keys are used as decryption only.

By default, connections to memcached server are not encrypted. To enable encryption, use tls keyword in --tls-ticket-key-memcached option.

If --tls-ticket-key-file is given, encryption key is read from the given file. In this case, nghttpx does not rotate key automatically. To rotate key, one has to restart nghttpx (see SIGNALS).

CERTIFICATE TRANSPARENCY

nghttpx supports TLS signed_certificate_timestamp extension (RFC 6962). The relevant options are --tls-sct-dir and sct-dir parameter in --subcert. They takes a directory, and nghttpx reads all files whose extension is .sct under the directory. The *.sct files are encoded as SignedCertificateTimestamp struct described in section 3.2 of RFC 69662. This format is the same one used by nginx-ct and mod_ssl_ct. ct-submit can be used to submit certificates to log servers, and obtain the SignedCertificateTimestamp struct which can be used with nghttpx.

MRUBY SCRIPTING

WARNING: The current mruby extension API is experimental and not frozen. The API is subject to change in the future release.

WARNING: Almost all string value returned from method, or attribute is a fresh new mruby string, which involves memory allocation, and copies. Therefore, it is strongly recommended to store a return value in a local variable, and use it, instead of calling method or accessing attribute repeatedly.

nghttpx allows users to extend its capability using mruby scripts. nghttpx has 2 hook points to execute mruby script: request phase and response phase. The request phase hook is invoked after all request header fields are received from client. The response phase hook is invoked after all response header fields are received from backend server. These hooks allows users to modify header fields, or common HTTP variables, like authority or request path, and even return custom response without forwarding request to backend servers.

There are 2 levels of mruby script invocations: global and per-pattern. The global mruby script is set by --mruby-file option and is called for all requests. The per-pattern mruby script is set by "mruby" parameter in -b option. It is invoked for a request which matches the particular pattern. The order of hook invocation is: global request phase hook, per-pattern request phase hook, per-pattern response phase hook, and finally global response phase hook. If a hook returns a response, any later hooks are not invoked. The global request hook is invoked before the pattern matching is made and changing request path may affect the pattern matching.

Please note that request and response hooks of per-pattern mruby script for a single request might not come from the same script. This might happen after a request hook is executed, backend failed for some reason, and at the same time, backend configuration is replaced by API request, and then the request uses new configuration on retry. The response hook from new configuration, if it is specified, will be invoked.

The all mruby script will be evaluated once per thread on startup, and it must instantiate object and evaluate it as the return value (e.g., App.new). This object is called app object. If app object defines on_req method, it is called with Nghttpx::Env object on request hook. Similarly, if app object defines on_resp method, it is called with Nghttpx::Env object on response hook. For each method invocation, user can can access Nghttpx::Request and Nghttpx::Response objects via Nghttpx::Env#req and Nghttpx::Env#resp respectively.

Nghttpx::REQUEST_PHASE
    Constant to represent request phase.

Nghttpx::RESPONSE_PHASE
    Constant to represent response phase.

class Nghttpx::Env
    Object to represent current request specific context.

attribute [R] req
    Return Request object.

attribute [R] resp
    Return Response object.

attribute [R] ctx
    Return Ruby hash object. It persists until request finishes. So values set in request phase hook can be retrieved in response phase hook.

attribute [R] phase
    Return the current phase.

attribute [R] remote_addr
    Return IP address of a remote client. If connection is made via UNIX domain socket, this returns the string "localhost".

attribute [R] server_addr
    Return address of server that accepted the connection. This is a string which specified in --frontend option, excluding port number, and not a resolved IP address. For UNIX domain socket, this is a path to UNIX domain socket.

attribute [R] server_port
    Return port number of the server frontend which accepted the connection from client.

attribute [R] tls_used
    Return true if TLS is used on the connection.

attribute [R] tls_sni
    Return the TLS SNI value which client sent in this connection.

attribute [R] tls_client_fingerprint_sha256
    Return the SHA-256 fingerprint of a client certificate.

attribute [R] tls_client_fingerprint_sha1
    Return the SHA-1 fingerprint of a client certificate.

attribute [R] tls_client_issuer_name
    Return the issuer name of a client certificate.

attribute [R] tls_client_subject_name
    Return the subject name of a client certificate.

attribute [R] tls_client_serial
    Return the serial number of a client certificate.

attribute [R] tls_client_not_before
    Return the start date of a client certificate in seconds since the epoch.

attribute [R] tls_client_not_after
    Return the end date of a client certificate in seconds since the epoch.

attribute [R] tls_cipher
    Return a TLS cipher negotiated in this connection.

attribute [R] tls_protocol
    Return a TLS protocol version negotiated in this connection.

attribute [R] tls_session_id
    Return a session ID for this connection in hex string.

attribute [R] tls_session_reused
    Return true if, and only if a SSL/TLS session is reused.

attribute [R] alpn
    Return ALPN identifier negotiated in this connection.

attribute [R] tls_handshake_finished
    Return true if SSL/TLS handshake has finished. If it returns false in the request phase hook, the request is received in TLSv1.3 early data (0-RTT) and might be vulnerable to the replay attack. nghttpx will send Early-Data header field to backend servers to indicate this.

class Nghttpx::Request
    Object to represent request from client. The modification to Request object is allowed only in request phase hook.

attribute [R] http_version_major
    Return HTTP major version.

attribute [R] http_version_minor
    Return HTTP minor version.

attribute [R/W] method
    HTTP method. On assignment, copy of given value is assigned. We don't accept arbitrary method name. We will document them later, but well known methods, like GET, PUT and POST, are all supported.

attribute [R/W] authority
    Authority (i.e., example.org), including optional port component . On assignment, copy of given value is assigned.

attribute [R/W] scheme
    Scheme (i.e., http, https). On assignment, copy of given value is assigned.

attribute [R/W] path
    Request path, including query component (i.e., /index.html). On assignment, copy of given value is assigned. The path does not include authority component of URI. This may include query component. nghttpx makes certain normalization for path. It decodes percent-encoding for unreserved characters (see https://tools.ietf.org/html/rfc3986#section-2.3), and resolves ".." and ".". But it may leave characters which should be percent-encoded as is. So be careful when comparing path against desired string.

attribute [R] headers
    Return Ruby hash containing copy of request header fields. Changing values in returned hash does not change request header fields actually used in request processing. Use Nghttpx::Request#add_header or Nghttpx::Request#set_header to change request header fields.

add_header(key, value)
    Add header entry associated with key. The value can be single string or array of string. It does not replace any existing values associated with key.

set_header(key, value)
    Set header entry associated with key. The value can be single string or array of string. It replaces any existing values associated with key.

clear_headers()
    Clear all existing request header fields.

push(uri)
    Initiate to push resource identified by uri. Only HTTP/2 protocol supports this feature. For the other protocols, this method is noop. uri can be absolute URI, absolute path or relative path to the current request. For absolute or relative path, scheme and authority are inherited from the current request. Currently, method is always GET. nghttpx will issue request to backend servers to fulfill this request. The request and response phase hooks will be called for pushed resource as well.

class Nghttpx::Response
    Object to represent response from backend server.

attribute [R] http_version_major
    Return HTTP major version.

attribute [R] http_version_minor
    Return HTTP minor version.

attribute [R/W] status
    HTTP status code. It must be in the range [200, 999], inclusive. The non-final status code is not supported in mruby scripting at the moment.

attribute [R] headers
    Return Ruby hash containing copy of response header fields. Changing values in returned hash does not change response header fields actually used in response processing. Use Nghttpx::Response#add_header or Nghttpx::Response#set_header to change response header fields.

add_header(key, value)
    Add header entry associated with key. The value can be single string or array of string. It does not replace any existing values associated with key.

set_header(key, value)
    Set header entry associated with key. The value can be single string or array of string. It replaces any existing values associated with key.

clear_headers()
    Clear all existing response header fields.

return(body)
    Return custom response body to a client. When this method is called in request phase hook, the request is not forwarded to the backend, and response phase hook for this request will not be invoked. When this method is called in response phase hook, response from backend server is canceled and discarded. The status code and response header fields should be set before using this method. To set status code, use Nghttpx::Response#status. If status code is not set, 200 is used. To set response header fields, Nghttpx::Response#add_header and Nghttpx::Response#set_header. When this method is invoked in response phase hook, the response headers are filled with the ones received from backend server. To send completely custom header fields, first call Nghttpx::Response#clear_headers to erase all existing header fields, and then add required header fields. It is an error to call this method twice for a given request.

send_info(status, headers)
    Send non-final (informational) response to a client. status must be in the range [100, 199], inclusive. headers is a hash containing response header fields. Its key must be a string, and the associated value must be either string or array of strings. Since this is not a final response, even if this method is invoked, request is still forwarded to a backend unless Nghttpx::Response#return is called. This method can be called multiple times. It cannot be called after Nghttpx::Response#return is called.

  MRUBY EXAMPLES

Modify request path:

class App
  def on_req(env)
    env.req.path = "/apps#{env.req.path}"
  end
end
App.new

Don't forget to instantiate and evaluate object at the last line.

Restrict permission of viewing a content to a specific client addresses:

class App
  def on_req(env)
    allowed_clients = ["127.0.0.1", "::1"]
    if env.req.path.start_with?("/log/") &&
       !allowed_clients.include?(env.remote_addr) then
      env.resp.status = 404
      env.resp.return "permission denied"
    end
  end
end
App.new

API ENDPOINTS

nghttpx exposes API endpoints to manipulate it via HTTP based API. By default, API endpoint is disabled. To enable it, add a dedicated frontend for API using --frontend option with "api" parameter. All requests which come from this frontend address, will be treated as API request.

The response is normally JSON dictionary, and at least includes the following keys:

status
    The status of the request processing. The following values are defined:

Success
    The request was successful.

Failure
    The request was failed. No change has been made.

code
    HTTP status code

    Additionally, depending on the API endpoint, data key may be present, and its value contains the API endpoint specific data.

    We wrote "normally", since nghttpx may return ordinal HTML response in some cases where the error has occurred before reaching API endpoint (e.g., header field is too large).

    The following section describes available API endpoints.

  POST /api/v1beta1/backendconfig

This API replaces the current backend server settings with the requested ones. The request method should be POST, but PUT is also acceptable. The request body must be nghttpx configuration file format. For configuration file format, see FILES section. The line separator inside the request body must be single LF (0x0A). Currently, only backend option is parsed, the others are simply ignored. The semantics of this API is replace the current backend with the backend options in request body. Describe the desired set of backend severs, and nghttpx makes it happen. If there is no backend option is found in request body, the current set of backend is replaced with the backend option's default value, which is 127.0.0.1,80.

The replacement is done instantly without breaking existing connections or requests. It also avoids any process creation as is the case with hot swapping with signals.

The one limitation is that only numeric IP address is allowed in backend in request body unless "dns" parameter is used while non numeric hostname is allowed in command-line or configuration file is read using --conf.

  GET /api/v1beta1/configrevision

This API returns configuration revision of the current nghttpx. The configuration revision is opaque string, and it changes after each reloading by SIGHUP. With this API, an external application knows that whether nghttpx has finished reloading its configuration by comparing the configuration revisions between before and after reloading. It is recommended to disable persistent (keep-alive) connection for this purpose in order to avoid to send a request using the reused connection which may bound to an old process.

This API returns response including data key. Its value is JSON object, and it contains at least the following key:

configRevision
    The configuration revision of the current nghttpx

SEE ALSO

nghttp(1), nghttpd(1), h2load(1)

AUTHOR
Tatsuhiro Tsujikawa

COPYRIGHT
2012, 2015, 2016, Tatsuhiro Tsujikawa