.\" Man page generated from reStructuredText. . .TH "NGHTTPX" "1" "May 07, 2015" "0.7.14-DEV" "nghttp2" .SH NAME nghttpx \- HTTP/2 experimental proxy . .nr rst2man-indent-level 0 . .de1 rstReportMargin \\$1 \\n[an-margin] level \\n[rst2man-indent-level] level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] - \\n[rst2man-indent0] \\n[rst2man-indent1] \\n[rst2man-indent2] .. .de1 INDENT .\" .rstReportMargin pre: . RS \\$1 . nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin] . nr rst2man-indent-level +1 .\" .rstReportMargin post: .. .de UNINDENT . RE .\" indent \\n[an-margin] .\" old: \\n[rst2man-indent\\n[rst2man-indent-level]] .nr rst2man-indent-level -1 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]] .in \\n[rst2man-indent\\n[rst2man-indent-level]]u .. .SH SYNOPSIS .sp \fBnghttpx\fP [OPTIONS]... [ ] .SH DESCRIPTION .sp A reverse proxy for HTTP/2, HTTP/1 and SPDY. .INDENT 0.0 .TP .B Set path to server\(aqs private key. Required unless \fI\%\-p\fP, \fI\%\-\-client\fP or \fI\%\-\-frontend\-no\-tls\fP are given. .UNINDENT .INDENT 0.0 .TP .B Set path to server\(aqs certificate. Required unless \fI\%\-p\fP, \fI\%\-\-client\fP or \fI\%\-\-frontend\-no\-tls\fP are given. To make OCSP stapling work, this must be absolute path. .UNINDENT .SH OPTIONS .sp The options are categorized into several groups. .SS Connections .INDENT 0.0 .TP .B \-b, \-\-backend= 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) .sp Default: \fB127.0.0.1,80\fP .UNINDENT .INDENT 0.0 .TP .B \-f, \-\-frontend= Set frontend host and port. If is \(aq*\(aq, 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) .sp Default: \fB*,3000\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backlog= Set listen backlog size. .sp Default: \fB512\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-ipv4 Resolve backend hostname to IPv4 address only. .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-ipv6 Resolve backend hostname to IPv6 address only. .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-http\-proxy\-uri= Specify proxy URI in the form \fI\%http:/\fP/[:@]:. If a proxy requires authentication, specify and . 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 \fI\%\-\-backend\-read\-timeout\fP and \fI\%\-\-backend\-write\-timeout\fP options. .UNINDENT .SS Performance .INDENT 0.0 .TP .B \-n, \-\-workers= Set the number of worker threads. .sp Default: \fB1\fP .UNINDENT .INDENT 0.0 .TP .B \-\-read\-rate= Set maximum average read rate on frontend connection. Setting 0 to this option means read rate is unlimited. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-read\-burst= Set maximum read burst size on frontend connection. Setting 0 to this option means read burst size is unlimited. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-write\-rate= Set maximum average write rate on frontend connection. Setting 0 to this option means write rate is unlimited. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-write\-burst= Set maximum write burst size on frontend connection. Setting 0 to this option means write burst size is unlimited. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-worker\-read\-rate= Set maximum average read rate on frontend connection per worker. Setting 0 to this option means read rate is unlimited. Not implemented yet. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-worker\-read\-burst= Set maximum read burst size on frontend connection per worker. Setting 0 to this option means read burst size is unlimited. Not implemented yet. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-worker\-write\-rate= Set maximum average write rate on frontend connection per worker. Setting 0 to this option means write rate is unlimited. Not implemented yet. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-worker\-write\-burst= Set maximum write burst size on frontend connection per worker. Setting 0 to this option means write burst size is unlimited. Not implemented yet. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-worker\-frontend\-connections= Set maximum number of simultaneous connections frontend accepts. Setting 0 means unlimited. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-http2\-connections\-per\-worker= Set maximum number of HTTP/2 connections per worker. The default value is 0, which means the number of backend addresses specified by \fI\%\-b\fP option. .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-http1\-connections\-per\-host= Set maximum number of backend concurrent HTTP/1 connections per host. This option is meaningful when \fI\%\-s\fP option is used. To limit the number of connections per frontend for default mode, use \fI\%\-\-backend\-http1\-connections\-per\-frontend\fP\&. .sp Default: \fB8\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-http1\-connections\-per\-frontend= Set maximum number of backend concurrent HTTP/1 connections per frontend. This option is only used for default mode. 0 means unlimited. To limit the number of connections per host for HTTP/2 or SPDY proxy mode (\-s option), use \fI\%\-\-backend\-http1\-connections\-per\-host\fP\&. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-rlimit\-nofile= Set maximum number of open files (RLIMIT_NOFILE) to . If 0 is given, nghttpx does not set the limit. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-request\-buffer= Set buffer size used to store backend request. .sp Default: \fB16K\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-response\-buffer= Set buffer size used to store backend response. .sp Default: \fB16K\fP .UNINDENT .SS Timeout .INDENT 0.0 .TP .B \-\-frontend\-http2\-read\-timeout= Specify read timeout for HTTP/2 and SPDY frontend connection. .sp Default: \fB3m\fP .UNINDENT .INDENT 0.0 .TP .B \-\-frontend\-read\-timeout= Specify read timeout for HTTP/1.1 frontend connection. .sp Default: \fB3m\fP .UNINDENT .INDENT 0.0 .TP .B \-\-frontend\-write\-timeout= Specify write timeout for all frontend connections. .sp Default: \fB30s\fP .UNINDENT .INDENT 0.0 .TP .B \-\-stream\-read\-timeout= Specify read timeout for HTTP/2 and SPDY streams. 0 means no timeout. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-stream\-write\-timeout= Specify write timeout for HTTP/2 and SPDY streams. 0 means no timeout. .sp Default: \fB0\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-read\-timeout= Specify read timeout for backend connection. .sp Default: \fB3m\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-write\-timeout= Specify write timeout for backend connection. .sp Default: \fB30s\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-keep\-alive\-timeout= Specify keep\-alive timeout for backend connection. .sp Default: \fB2s\fP .UNINDENT .INDENT 0.0 .TP .B \-\-listener\-disable\-timeout= After accepting connection failed, connection listener is disabled for a given amount of time. Specifying 0 disables this feature. .sp Default: \fB0\fP .UNINDENT .SS SSL/TLS .INDENT 0.0 .TP .B \-\-ciphers= Set allowed cipher list. The format of the string is described in OpenSSL ciphers(1). .UNINDENT .INDENT 0.0 .TP .B \-k, \-\-insecure Don\(aqt verify backend server\(aqs certificate if \fI\%\-p\fP, \fI\%\-\-client\fP or \fI\%\-\-http2\-bridge\fP are given and \fI\%\-\-backend\-no\-tls\fP is not given. .UNINDENT .INDENT 0.0 .TP .B \-\-cacert= Set path to trusted CA certificate file if \fI\%\-p\fP, \fI\%\-\-client\fP or \fI\%\-\-http2\-bridge\fP are given and \fI\%\-\-backend\-no\-tls\fP is not given. 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. .UNINDENT .INDENT 0.0 .TP .B \-\-private\-key\-passwd\-file= Path to file that contains password for the server\(aqs private key. If none is given and the private key is password protected it\(aqll be requested interactively. .UNINDENT .INDENT 0.0 .TP .B \-\-subcert=: Specify additional certificate and private key file. nghttpx will choose certificates based on the hostname indicated by client using TLS SNI extension. This option can be used multiple times. To make OCSP stapling work, must be absolute path. .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-tls\-sni\-field= Explicitly set the content of the TLS SNI extension. This will default to the backend HOST name. .UNINDENT .INDENT 0.0 .TP .B \-\-dh\-param\-file= Path to file that contains DH parameters in PEM format. Without this option, DHE cipher suites are not available. .UNINDENT .INDENT 0.0 .TP .B \-\-npn\-list= Comma delimited list of ALPN protocol identifier sorted in the order of preference. That means most desirable protocol comes first. This is used in both ALPN and NPN. The parameter must be delimited by a single comma only and any white spaces are treated as a part of protocol string. .sp Default: \fBh2,h2\-16,h2\-14,spdy/3.1,http/1.1\fP .UNINDENT .INDENT 0.0 .TP .B \-\-verify\-client Require and verify client certificate. .UNINDENT .INDENT 0.0 .TP .B \-\-verify\-client\-cacert= Path to file that contains CA certificates to verify client certificate. The file must be in PEM format. It can contain multiple certificates. .UNINDENT .INDENT 0.0 .TP .B \-\-client\-private\-key\-file= Path to file that contains client private key used in backend client authentication. .UNINDENT .INDENT 0.0 .TP .B \-\-client\-cert\-file= Path to file that contains client certificate used in backend client authentication. .UNINDENT .INDENT 0.0 .TP .B \-\-tls\-proto\-list= Comma delimited list of SSL/TLS protocol to be enabled. The following protocols are available: TLSv1.2, TLSv1.1 and TLSv1.0. The name matching is done in case\-insensitive manner. The parameter must be delimited by a single comma only and any white spaces are treated as a part of protocol string. .sp Default: \fBTLSv1.2,TLSv1.1\fP .UNINDENT .INDENT 0.0 .TP .B \-\-tls\-ticket\-key\-file= Path to file that contains 48 bytes random data to construct TLS session ticket parameters. 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 automatically and renewed every 12hrs. At most 2 keys are stored in memory. .UNINDENT .INDENT 0.0 .TP .B \-\-fetch\-ocsp\-response\-file= Path to fetch\-ocsp\-response script file. It should be absolute path. .sp Default: \fB/usr/local/share/nghttp2/fetch\-ocsp\-response\fP .UNINDENT .INDENT 0.0 .TP .B \-\-ocsp\-update\-interval= Set interval to update OCSP response cache. .sp Default: \fB4h\fP .UNINDENT .INDENT 0.0 .TP .B \-\-no\-ocsp Disable OCSP stapling. .UNINDENT .SS HTTP/2 and SPDY .INDENT 0.0 .TP .B \-c, \-\-http2\-max\-concurrent\-streams= Set the maximum number of the concurrent streams in one HTTP/2 and SPDY session. .sp Default: \fB100\fP .UNINDENT .INDENT 0.0 .TP .B \-\-frontend\-http2\-window\-bits= Sets the per\-stream initial window size of HTTP/2 SPDY frontend connection. For HTTP/2, the size is 2**\-1. For SPDY, the size is 2**. .sp Default: \fB16\fP .UNINDENT .INDENT 0.0 .TP .B \-\-frontend\-http2\-connection\-window\-bits= Sets the per\-connection window size of HTTP/2 and SPDY frontend connection. For HTTP/2, the size is 2**\-1. For SPDY, the size is 2**. .sp Default: \fB16\fP .UNINDENT .INDENT 0.0 .TP .B \-\-frontend\-no\-tls Disable SSL/TLS on frontend connections. .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-http2\-window\-bits= Sets the initial window size of HTTP/2 backend connection to 2**\-1. .sp Default: \fB16\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-http2\-connection\-window\-bits= Sets the per\-connection window size of HTTP/2 backend connection to 2**\-1. .sp Default: \fB16\fP .UNINDENT .INDENT 0.0 .TP .B \-\-backend\-no\-tls Disable SSL/TLS on backend connections. .UNINDENT .INDENT 0.0 .TP .B \-\-http2\-no\-cookie\-crumbling Don\(aqt crumble cookie header field. .UNINDENT .INDENT 0.0 .TP .B \-\-padding= Add at most 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. .UNINDENT .INDENT 0.0 .TP .B \-\-no\-server\-push Disable HTTP/2 server push. Server push is only supported by default mode and HTTP/2 frontend. SPDY frontend does not support server push. .UNINDENT .SS Mode .INDENT 0.0 .TP .B (default mode) Accept HTTP/2, SPDY and HTTP/1.1 over SSL/TLS. If \fI\%\-\-frontend\-no\-tls\fP is used, accept HTTP/2 and HTTP/1.1. The incoming HTTP/1.1 connection can be upgraded to HTTP/2 through HTTP Upgrade. The protocol to the backend is HTTP/1.1. .UNINDENT .INDENT 0.0 .TP .B \-s, \-\-http2\-proxy Like default mode, but enable secure proxy mode. .UNINDENT .INDENT 0.0 .TP .B \-\-http2\-bridge Like default mode, but communicate with the backend in HTTP/2 over SSL/TLS. Thus the incoming all connections are converted to HTTP/2 connection and relayed to the backend. See \fI\%\-\-backend\-http\-proxy\-uri\fP option if you are behind the proxy and want to connect to the outside HTTP/2 proxy. .UNINDENT .INDENT 0.0 .TP .B \-\-client Accept HTTP/2 and HTTP/1.1 without SSL/TLS. The incoming HTTP/1.1 connection can be upgraded to HTTP/2 connection through HTTP Upgrade. The protocol to the backend is HTTP/2. To use nghttpx as a forward proxy, use \fI\%\-p\fP option instead. .UNINDENT .INDENT 0.0 .TP .B \-p, \-\-client\-proxy Like \fI\%\-\-client\fP option, but it also requires the request path from frontend must be an absolute URI, suitable for use as a forward proxy. .UNINDENT .SS Logging .INDENT 0.0 .TP .B \-L, \-\-log\-level= Set the severity level of log output. must be one of INFO, NOTICE, WARN, ERROR and FATAL. .sp Default: \fBNOTICE\fP .UNINDENT .INDENT 0.0 .TP .B \-\-accesslog\-file= Set path to write access log. To reopen file, send USR1 signal to nghttpx. .UNINDENT .INDENT 0.0 .TP .B \-\-accesslog\-syslog Send access log to syslog. If this option is used, \fI\%\-\-accesslog\-file\fP option is ignored. .UNINDENT .INDENT 0.0 .TP .B \-\-accesslog\-format= Specify format string for access log. The default format is combined format. The following variables are available: .INDENT 7.0 .IP \(bu 2 $remote_addr: client IP address. .IP \(bu 2 $time_local: local time in Common Log format. .IP \(bu 2 $time_iso8601: local time in ISO 8601 format. .IP \(bu 2 $request: HTTP request line. .IP \(bu 2 $status: HTTP response status code. .IP \(bu 2 $body_bytes_sent: the number of bytes sent to client as response body. .IP \(bu 2 $http_: value of HTTP request header where \(aq_\(aq in is replaced with \(aq\-\(aq. .IP \(bu 2 $remote_port: client port. .IP \(bu 2 $server_port: server port. .IP \(bu 2 $request_time: request processing time in seconds with milliseconds resolution. .IP \(bu 2 $pid: PID of the running process. .IP \(bu 2 $alpn: ALPN identifier of the protocol which generates the response. For HTTP/1, ALPN is always http/1.1, regardless of minor version. .UNINDENT .sp Default: \fB$remote_addr \- \- [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent"\fP .UNINDENT .INDENT 0.0 .TP .B \-\-errorlog\-file= Set path to write error log. To reopen file, send USR1 signal to nghttpx. stderr will be redirected to the error log file unless \fI\%\-\-errorlog\-syslog\fP is used. .sp Default: \fB/dev/stderr\fP .UNINDENT .INDENT 0.0 .TP .B \-\-errorlog\-syslog Send error log to syslog. If this option is used, \fI\%\-\-errorlog\-file\fP option is ignored. .UNINDENT .INDENT 0.0 .TP .B \-\-syslog\-facility= Set syslog facility to . .sp Default: \fBdaemon\fP .UNINDENT .SS HTTP .INDENT 0.0 .TP .B \-\-add\-x\-forwarded\-for Append X\-Forwarded\-For header field to the downstream request. .UNINDENT .INDENT 0.0 .TP .B \-\-strip\-incoming\-x\-forwarded\-for Strip X\-Forwarded\-For header field from inbound client requests. .UNINDENT .INDENT 0.0 .TP .B \-\-no\-via Don\(aqt append to Via header field. If Via header field is received, it is left unaltered. .UNINDENT .INDENT 0.0 .TP .B \-\-no\-location\-rewrite Don\(aqt rewrite location header field on \fI\%\-\-http2\-bridge\fP, \fI\%\-\-client\fP and default mode. For \fI\%\-\-http2\-proxy\fP and \fI\%\-\-client\-proxy\fP mode, location header field will not be altered regardless of this option. .UNINDENT .INDENT 0.0 .TP .B \-\-no\-host\-rewrite Don\(aqt rewrite host and :authority header fields on \fI\%\-\-http2\-bridge\fP, \fI\%\-\-client\fP and default mode. For \fI\%\-\-http2\-proxy\fP and \fI\%\-\-client\-proxy\fP mode, these headers will not be altered regardless of this option. .UNINDENT .INDENT 0.0 .TP .B \-\-altsvc= Specify protocol ID, port, host and origin of alternative service. and are optional. They are advertised in alt\-svc header field or HTTP/2 ALTSVC frame. This option can be used multiple times to specify multiple alternative services. Example: \fI\%\-\-altsvc\fP=h2,443 .UNINDENT .INDENT 0.0 .TP .B \-\-add\-response\-header=
Specify additional header field to add to response header set. This option just appends header field and won\(aqt replace anything already set. This option can be used several times to specify multiple header fields. Example: \fI\%\-\-add\-response\-header\fP="foo: bar" .UNINDENT .INDENT 0.0 .TP .B \-\-header\-field\-buffer= Set maximum buffer size for incoming HTTP header field list. This is the sum of header name and value in bytes. .sp Default: \fB64K\fP .UNINDENT .INDENT 0.0 .TP .B \-\-max\-header\-fields= Set maximum number of incoming HTTP header fields, which appear in one request or response header field list. .sp Default: \fB100\fP .UNINDENT .SS Debug .INDENT 0.0 .TP .B \-\-frontend\-http2\-dump\-request\-header= Dumps request headers received by HTTP/2 frontend to the file denoted in . 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 \fI\%\-n\fP, where >= 2. .UNINDENT .INDENT 0.0 .TP .B \-\-frontend\-http2\-dump\-response\-header= Dumps response headers sent from HTTP/2 frontend to the file denoted in . 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 \fI\%\-n\fP, where >= 2. .UNINDENT .INDENT 0.0 .TP .B \-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 \fI\%\-n\fP=N, where N >= 2. .UNINDENT .SS Process .INDENT 0.0 .TP .B \-D, \-\-daemon Run in a background. If \fI\%\-D\fP is used, the current working directory is changed to \(aq\fI/\fP\(aq. .UNINDENT .INDENT 0.0 .TP .B \-\-pid\-file= Set path to save PID of this program. .UNINDENT .INDENT 0.0 .TP .B \-\-user= Run this program as . This option is intended to be used to drop root privileges. .UNINDENT .SS Misc .INDENT 0.0 .TP .B \-\-conf= Load configuration from . .sp Default: \fB/etc/nghttpx/nghttpx.conf\fP .UNINDENT .INDENT 0.0 .TP .B \-v, \-\-version Print version and exit. .UNINDENT .INDENT 0.0 .TP .B \-h, \-\-help Print this help and exit. .UNINDENT .sp The argument is an integer and an optional unit (e.g., 10K is 10 * 1024). Units are K, M and G (powers of 1024). .sp The 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. .SH FILES .INDENT 0.0 .TP .B \fI/etc/nghttpx/nghttpx.conf\fP The default configuration file path nghttpx searches at startup. The configuration file path can be changed using \fI\%\-\-conf\fP option. .sp Those lines which are staring \fB#\fP are treated as comment. .sp The option name in the configuration file is the long command\-line option name with leading \fB\-\-\fP stripped (e.g., \fBfrontend\fP). Put \fB=\fP between option name and value. Don\(aqt put extra leading or trailing spaces. .sp The options which do not take argument in the command\-line \fItake\fP argument in the configuration file. Specify \fByes\fP as an argument (e.g., \fBhttp2\-proxy=yes\fP). If other string is given, it is ignored. .sp To specify private key and certificate file which are given as positional arguments in commnad\-line, use \fBprivate\-key\-file\fP and \fBcertificate\-file\fP\&. .sp \fI\%\-\-conf\fP option cannot be used in the configuration file and will be ignored if specified. .UNINDENT .SH SIGNALS .INDENT 0.0 .TP .B SIGQUIT Shutdown gracefully. First accept pending connections and stop accepting connection. After all connections are handled, nghttpx exits. .TP .B SIGUSR1 Reopen log files. .TP .B SIGUSR2 Fork and execute nghttpx. It will execute the binary in the same path with same command\-line arguments and environment variables. After new process comes up, sending SIGQUIT to the original process to perform hot swapping. .UNINDENT .SH SERVER PUSH .sp nghttpx supports HTTP/2 server push in default mode. nghttpx looks for Link header field (\fI\%RFC 5988\fP) in response headers from backend server and extracts URI\-reference with parameter \fBrel=preload\fP (see \fI\%preload\fP) and pushes those URIs to the frontend client. Here is a sample Link header field to initiate server push: .INDENT 0.0 .INDENT 3.5 .sp .nf .ft C Link: ; rel=preload Link: ; rel=preload .ft P .fi .UNINDENT .UNINDENT .sp Currently, the following restrictions are applied for server push: .INDENT 0.0 .IP 1. 3 URI\-reference must not contain authority. If it exists, it is not pushed. \fB/fonts/font.woff\fP and \fBcss/theme.css\fP are eligible to be pushed. \fBhttps://example.org/fonts/font.woff\fP and \fB//example.org/css/theme.css\fP are not. .IP 2. 3 The associated stream must have method "GET" or "POST". The associated stream\(aqs status code must be 200. .UNINDENT .sp These limitations may be loosened in the future release. .SH UNIX DOMAIN SOCKET .sp nghttpx supports UNIX domain socket with a filename for both frontend and backend connections. .sp 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. .SH OCSP STAPLING .sp OCSP query is done using external perl script \fBfetch\-ocsp\-response\fP, which has been developed as part of h2o project (\fI\%https://github.com/h2o/h2o\fP). .sp The script file is usually installed under \fB$(prefix)/share/nghttp2/\fP directory. The actual path to script can be customized using \fI\%\-\-fetch\-ocsp\-response\-file\fP option. .SH SEE ALSO .sp \fInghttp(1)\fP, \fInghttpd(1)\fP, \fIh2load(1)\fP .SH AUTHOR Tatsuhiro Tsujikawa .SH COPYRIGHT 2012, 2015, Tatsuhiro Tsujikawa .\" Generated by docutils manpage writer. .