.\"	$OpenBSD: httpd.conf.5,v 1.119 2021/10/24 16:01:04 ian Exp $
.\"
.\" Copyright (c) 2014, 2015 Reyk Floeter <reyk@openbsd.org>
.\"
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.\" purpose with or without fee is hereby granted, provided that the above
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.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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.Dd $Mdocdate: October 24 2021 $
.Dt HTTPD.CONF 5
.Os
.Sh NAME
.Nm httpd.conf
.Nd HTTP daemon configuration file
.Sh DESCRIPTION
.Nm
is the configuration file for the HTTP daemon,
.Xr httpd 8 .
.Pp
.Nm
is divided into the following main sections:
.Bl -tag -width xxxx
.It Sy Macros
User-defined variables may be defined and used later, simplifying the
configuration file.
.It Sy Global Configuration
Global settings for
.Xr httpd 8 .
.It Sy Servers
Listening HTTP web servers.
.It Sy Types
Media types and extensions.
.El
.Pp
Within the sections,
a host
.Ar address
can be specified by IPv4 address, IPv6 address, interface name,
interface group, or DNS hostname.
If the address is an interface name,
.Xr httpd 8
will look up the first IPv4 address and any other IPv4 and IPv6
addresses of the specified network interface.
If
.Sq *
is given as an address,
.Xr httpd 8
will listen on all IPv4 and IPv6 addresses.
.Ar 0.0.0.0
means to listen on all IPv4 addresses and
.Ar ::
all IPv6 addresses.
A
.Ar port
can be specified by number or name.
The port name to number mappings are found in the file
.Pa /etc/services ;
see
.Xr services 5
for details.
.Pp
The current line can be extended over multiple lines using a backslash
.Pq Sq \e .
Comments can be put anywhere in the file using a hash mark
.Pq Sq # ,
and extend to the end of the current line.
Care should be taken when commenting out multi-line text:
the comment is effective until the end of the entire block.
.Pp
Argument names not beginning with a letter, digit, or underscore
must be quoted.
.Pp
Additional configuration files can be included with the
.Ic include
keyword, for example:
.Bd -literal -offset indent
include "/etc/httpd.conf.local"
.Ed
.Sh MACROS
Macros can be defined that will later be expanded in context.
Macro names must start with a letter, digit, or underscore,
and may contain any of those characters.
Macro names may not be reserved words (for example,
.Ic directory ,
.Ic log ,
or
.Ic root ) .
Macros are not expanded inside quotes.
.Pp
For example:
.Bd -literal -offset indent
ext_ip="10.0.0.1"
server "default" {
	listen on $ext_ip port 80
}
.Ed
.Sh GLOBAL CONFIGURATION
Here are the settings that can be set globally:
.Bl -tag -width Ds
.It Ic chroot Ar directory
Set the
.Xr chroot 2
directory.
If not specified, it defaults to
.Pa /var/www ,
the home directory of the www user.
.It Ic default type Ar type/subtype
Set the default media type that is used if the media type for a
specified extension is not found in the configured types or for files
without a file extension;
see the
.Sx TYPES
section below.
If not specified, the default type is set to
.Ar application/octet-stream .
.It Ic errdocs Ar directory
Let
.Xr httpd 8
return custom error documents instead of the built-in ones.
.Pp
.Ar directory
is relative to the
.Ic chroot .
.Pp
Custom error documents are standalone
.Dq .html
files provided in one of the following ways:
.Bl -bullet -offset indent -compact
.It
As HTML files named after the 3-digit HTTP response code they are used
for, e.g.,
.Pa 404.html .
.It
As a generic template file named
.Pa err.html
which is used for response codes no dedicated file is provided for.
.El
.Pp
In case the latter does not exist and there is no dedicated file available for
a certain response code, the built-in error document will be used as fallback.
.Pp
A custom error document may contain the following macros that will be expanded
at runtime:
.Pp
.Bl -tag -width $RESPONSE_CODE -offset indent -compact
.It Ic $HTTP_ERROR
The error message text.
.It Ic $RESPONSE_CODE
The 3-digit HTTP response code sent to the client.
.It Ic $SERVER_SOFTWARE
The server software name of
.Xr httpd 8 .
.El
.It Ic logdir Ar directory
Specifies the full path of the directory in which log files will be written.
If not specified, it defaults to
.Pa /logs
within the
.Xr chroot 2
directory.
.It Ic prefork Ar number
Run the specified number of server processes.
This increases the performance and prevents delays when connecting
to a server.
.Xr httpd 8
runs 3 server processes by default.
.El
.Sh SERVERS
The configured web servers.
.Pp
Each
.Ic server
section starts with a declaration of the server
.Ar name :
.Bl -tag -width Ds
.It Ic server Ar name Brq ...
Match the server name using shell globbing rules.
This can be an explicit name,
.Ar www.example.com ,
or a name including wildcards,
.Ar *.example.com .
.It Ic server match Ar name Brq ...
Match the server name using pattern matching,
see
.Xr patterns 7 .
.El
.Pp
Followed by a block of options enclosed in curly braces:
.Bl -tag -width Ds
.It Ic alias Ar name
Specify an additional alias
.Ar name
for this server.
.It Ic alias match Ar name
Like the
.Ic alias
option,
but
.Ic match
the
.Ar name
using pattern matching instead of shell globbing rules,
see
.Xr patterns 7 .
.It Oo Ic no Oc Ic authenticate Oo Ar realm Oc Ic with Pa htpasswd
Authenticate a remote user for
.Ar realm
by checking the credentials against the user authentication file
.Pa htpasswd .
The file name is relative to the
.Ic chroot
and must be readable by the www user.
Use the
.Ic no authenticate
directive to disable authentication in a location.
.It Ic block drop
Drop the connection without sending an error page.
.It Ic block Op Ic return Ar code Op Ar uri
Close the connection and send an error page.
If the optional return code is not specified,
.Xr httpd 8
denies access with a
.Sq 403 Forbidden
response.
The optional
.Ar uri
argument can be used with return codes in the 3xx range to send an
HTTP Location header for redirection to a specified URI.
.Pp
It is possible to rewrite the request to redirect it to a different
external location.
The
.Ar uri
may contain predefined macros that will be expanded at runtime:
.Pp
.Bl -tag -width $DOCUMENT_URI -offset indent -compact
.It Ic $DOCUMENT_URI
The request path.
.It Ic $QUERY_STRING
The query string of the request.
.It Ic $QUERY_STRING_ENC
The URL-encoded query string of the request.
.It Ic $REMOTE_ADDR
The IP address of the connected client.
.It Ic $REMOTE_PORT
The TCP source port of the connected client.
.It Ic $REMOTE_USER
The remote user for HTTP authentication.
.It Ic $REQUEST_SCHEME
The request scheme (http or https).
.It Ic $REQUEST_URI
The request path and optional query string.
.It Ic $SERVER_ADDR
The configured IP address of the server.
.It Ic $SERVER_PORT
The configured TCP port of the server.
.It Ic $SERVER_NAME
The name of the server.
.It Ic $HTTP_HOST
The host from the HTTP Host header.
.It Pf % Ar n
The capture index
.Ar n
of a string that was captured by the enclosing
.Ic location match
option.
.El
.It Ic connection Ar option
Set the specified options and limits for HTTP connections.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Ic max request body Ar number
Set the maximum body size in bytes that the client can send to the server.
The default value is 1048576 bytes (1M).
.It Ic max requests Ar number
Set the maximum number of requests per persistent HTTP connection.
Persistent connections are negotiated using the Keep-Alive header in
HTTP/1.0 and enabled by default in HTTP/1.1.
The default maximum number of requests per connection is 100.
.It Ic request timeout Ar seconds
Specify the inactivity timeout for HTTP operations between client and server,
for example the maximum time to wait for a request from the client.
The default timeout is 60 seconds (1 minute).
The maximum is 2147483647 seconds (68 years).
.It Ic timeout Ar seconds
Specify the inactivity timeout in seconds for accepted sessions,
for example the maximum time to wait for I/O from the FastCGI backend.
The default timeout is 600 seconds (10 minutes).
The maximum is 2147483647 seconds (68 years).
.El
.It Ic default type Ar type/subtype
Set the default media type for the specified location,
overwriting the global setting.
.It Ic directory Ar option
Set the specified options when serving or accessing directories.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Oo Ic no Oc Ic auto index
If no index file is found, automatically generate a directory listing.
This is disabled by default.
.It Ic index Ar string
Set the directory index file.
If not specified, it defaults to
.Pa index.html .
.It Ic no index
Disable the directory index.
.Xr httpd 8
will neither display nor generate a directory index.
.El
.It Oo Ic no Oc Ic errdocs Ar directory
Overrides or, if the
.Ic no
keyword is given, disables globally defined custom error documents for the
current
.Ic server .
.It Oo Ic no Oc Ic fastcgi Oo Ar option Oc
Enable FastCGI instead of serving files.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Ic socket Oo Cm tcp Oc Ar socket Oo Ar port Oc
.Nm httpd
passes HTTP requests to a FastCGI handler listening on the socket
.Ar socket .
The
.Ar socket
can either be a UNIX domain socket or a TCP socket.
If the FastCGI handler is listening on a UNIX domain socket,
.Ar socket
is a local path name within the
.Xr chroot 2
root directory of
.Xr httpd 8
and defaults to
.Pa /run/slowcgi.sock .
Alternatively if
the FastCGI handler is listening on a TCP socket,
.Ar socket
is a hostname or an IP address.
If the
.Ar port
is not specified, it defaults to port 9000.
.It Ic strip Ar number
Strip
.Ar number
path components from the beginning of DOCUMENT_ROOT and
SCRIPT_FILENAME before sending them to the FastCGI server.
This allows FastCGI server chroot to be a directory under httpd chroot.
.It Ic param Ar variable value
Sets a variable that will be sent to the FastCGI server.
Each statement defines one variable.
.El
.Pp
The FastCGI handler will be given the following variables by default:
.Pp
.Bl -tag -width GATEWAY_INTERFACE -offset indent -compact
.It Ic DOCUMENT_ROOT
The document root in which the script is located as configured by the
.Ic root
option for the server or location that matches the request.
.It Ic GATEWAY_INTERFACE
The revision of the CGI specification used.
.It Ic HTTP_*
Additional HTTP headers the connected client sent in the request, if
any.
.It Ic HTTPS
A variable that is set to
.Qq on
when the server has been configured to use TLS.
This variable is omitted otherwise.
.It Ic REQUEST_URI
The path and optional query string as requested by the connected client.
.It Ic DOCUMENT_URI
The canonicalized request path, possibly with a slash or
directory index file name appended.
This is the same as
.Ic PATH_INFO
appended to
.Ic SCRIPT_NAME .
.It Ic SCRIPT_NAME
The virtual URI path to the script.
.It Ic PATH_INFO
The optional path appended after the script name in the request path.
This variable is an empty string if no path is appended after the
script name.
.It Ic SCRIPT_FILENAME
The absolute, physical path to the script within the
.Xr chroot 2
directory.
.It Ic QUERY_STRING
The optional query string of the request.
This variable is an empty
string if there is no query string in the request.
.It Ic REMOTE_ADDR
The IP address of the connected client.
.It Ic REMOTE_PORT
The TCP source port of the connected client.
.It Ic REMOTE_USER
The remote user when using HTTP authentication.
.It Ic REQUEST_METHOD
The HTTP method the connected client used when making the request.
.It Ic SERVER_ADDR
The configured IP address of the server.
.It Ic SERVER_NAME
The name of the server.
.It Ic SERVER_PORT
The configured TCP server port of the server.
.It Ic SERVER_PROTOCOL
The revision of the HTTP specification used.
.It Ic SERVER_SOFTWARE
The server software name of
.Xr httpd 8 .
.It Ic TLS_PEER_VERIFY
A variable that is set to a comma separated list of TLS client verification
features in use
.Pq omitted when TLS client verification is not in use .
.El
.It Ic hsts Oo Ar option Oc
Enable HTTP Strict Transport Security.
Valid options are:
.Bl -tag -width Ds
.It Ic max-age Ar seconds
Set the maximum time in seconds a receiving user agent should regard
this host as an HSTS host.
The default is one year.
.It Ic preload
Confirm and authenticate that the site is permitted to be included in
a browser's preload list.
.It Ic subdomains
Signal to the receiving user agent that this host and all sub domains
of the host's domain should be considered HSTS hosts.
.El
.It Ic listen on Ar address Oo Ic tls Oc Ic port Ar number
Set the listen address and port.
This statement can be specified multiple times.
.It Ic location Oo Oo Ic not Oc Ic found Oc Ar path Brq ...
Specify server configuration rules for a specific location.
The
.Ar path
argument will be matched against the request path with shell globbing rules.
Optionally, it is also possible to match for
.Ic found
(i.e. accessible) or
.Ic not found
request paths only.
In case of multiple location statements in the same context, the
first matching location statement will be put into effect, while all
later ones will be ignored.
Therefore it is advisable to match for more specific paths first
and for generic ones later on.
A location section may include most of the server configuration rules
except
.Ic alias ,
.Ic connection ,
.Ic errdocs ,
.Ic hsts ,
.Ic listen on ,
.Ic location ,
.Ic tcp
and
.Ic tls .
.It Ic location Oo Oo Ic not Oc Ic found Oc Ic match Ar path Brq ...
Like the
.Ic location
option,
but
.Ic match
the
.Ar path
using pattern matching instead of shell globbing rules,
see
.Xr patterns 7 .
The pattern may contain captures that can be used in an enclosed
.Ic block return
or
.Ic request rewrite
option.
.It Oo Ic no Oc Ic log Op Ar option
Set the specified logging options.
Logging is enabled by default using the standard
.Ic access
and
.Ic error
log files,
but can be changed per server or location.
Use the
.Ic no log
directive to disable logging of any requests.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Ic access Ar name
Set the
.Ar name
of the access log file relative to the log directory.
If not specified, it defaults to
.Pa access.log .
.It Ic error Ar name
Set the
.Ar name
of the error log file relative to the log directory.
If not specified, it defaults to
.Pa error.log .
.It Ic style Ar style
Set the logging style.
The
.Ar style
can be
.Cm common ,
.Cm combined ,
.Cm forwarded
or
.Cm connection .
The styles
.Cm common
and
.Cm combined
write a log entry after each request similar to the standard Apache
and nginx access log formats.
The style
.Cm forwarded
extends the style
.Cm combined
by appending two fields containing the values of the headers
.Ar X-Forwarded-For
and
.Ar X-Forwarded-Port .
The style
.Cm connection
writes a summarized log entry after each connection,
that can have multiple requests,
similar to the format that is used by
.Xr relayd 8 .
If not specified, the default is
.Cm common .
.It Oo Ic no Oc Ic syslog
Enable or disable logging to
.Xr syslog 3
instead of the log files.
.El
.It Ic pass
Disable any previous
.Ic block
in a location.
.It Ic request Ar option
Configure the options for the request path.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Oo Ic no Oc Ic rewrite Ar path
Enable or disable rewriting of the request.
Unlike the redirection with
.Ic block return ,
this will change the request path internally before
.Nm httpd
makes a final decision about the matching location.
The
.Ar path
argument may contain predefined macros that will be expanded at runtime.
See the
.Ic block return
option for the list of supported macros.
.It Ic strip Ar number
Strip
.Ar number
path components from the beginning of the request path before looking
up the stripped-down path at the document root.
.El
.It Ic root Ar directory
Configure the document root of the server.
The
.Ar directory
is a pathname within the
.Xr chroot 2
root directory of
.Nm httpd .
If not specified, it defaults to
.Pa /htdocs .
.It Ic tcp Ar option
Enable or disable the specified TCP/IP options; see
.Xr tcp 4
and
.Xr ip 4
for more information about the options.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Ic backlog Ar number
Set the maximum length the queue of pending connections may grow to.
The backlog option is 10 by default and is limited by the
.Va kern.somaxconn
.Xr sysctl 8
variable.
.It Ic ip minttl Ar number
This option for the underlying IP connection may be used to discard packets
with a TTL lower than the specified value.
This can be used to implement the
Generalized TTL Security Mechanism (GTSM)
according to RFC 5082.
.It Ic ip ttl Ar number
Change the default time-to-live value in the IP headers.
.It Oo Ic no Oc Ic nodelay
Enable the TCP NODELAY option for this connection.
This is recommended to avoid delays in the data stream.
.It Oo Ic no Oc Ic sack
Use selective acknowledgements for this connection.
.It Ic socket buffer Ar number
Set the socket-level buffer size for input and output for this
connection.
This will affect the TCP window size.
.El
.It Ic tls Ar option
Set the TLS configuration for the server.
These options are only used if TLS has been enabled via the listen directive.
Multiple options may be specified within curly braces.
Valid options are:
.Bl -tag -width Ds
.It Ic certificate Ar file
Specify the certificate to use for this server.
The
.Ar file
should contain a PEM encoded certificate.
The default is
.Pa /etc/ssl/server.crt .
.It Ic ciphers Ar string
Specify the TLS cipher string.
If not specified, the default value
.Qq HIGH:!aNULL
will be used (strong crypto cipher suites without anonymous DH).
See the CIPHERS section of
.Xr openssl 1
for information about SSL/TLS cipher suites and preference lists.
.It Ic client ca Ar cafile Oo Ic crl Ar crlfile Oc Op Ic optional
Require
.Po
or, if
.Ic optional
is specified, request but do not require
.Pc
TLS client certificates whose authenticity can be verified
against the CA certificate(s) in
.Ar cafile
in order to proceed beyond the TLS handshake.
With
.Ic crl
specified, additionally require that no certificate in the client chain be
listed as revoked in the CRL(s) in
.Ar crlfile .
CA certificates and CRLs should be PEM encoded.
.It Ic dhe Ar params
Specify the DHE parameters to use for DHE cipher suites.
Valid parameter values are none, legacy and auto.
For legacy a fixed key length of 1024 bits is used, whereas for auto the key
length is determined automatically.
The default is none, which disables DHE cipher suites.
.It Ic ecdhe Ar curves
Specify a comma separated list of elliptic curves to use for ECDHE cipher suites,
in order of preference.
The special value of "default" will use the default curves; see
.Xr tls_config_set_ecdhecurves 3
for further details.
.It Ic key Ar file
Specify the private key to use for this server.
The
.Ar file
should contain a PEM encoded private key and reside outside of the
.Xr chroot 2
root directory of
.Nm httpd .
The default is
.Pa /etc/ssl/private/server.key .
.It Ic ocsp Ar file
Specify an OCSP response to be stapled during TLS handshakes
with this server.
The
.Ar file
should contain a DER-format OCSP response retrieved from an
OCSP server for the
.Ar certificate
in use,
and can be created using
.Xr ocspcheck 8 .
The path to
.Ar file
is not relative to the chroot.
If the OCSP response in
.Ar file
is empty, OCSP stapling will not be used.
The default is to not use OCSP stapling.
.It Ic protocols Ar string
Specify the TLS protocols to enable for this server.
Refer to the
.Xr tls_config_parse_protocols 3
function for valid protocol string values.
By default, TLSv1.3 and TLSv1.2 will be used.
.It Ic ticket lifetime Ar seconds
Enable TLS session tickets with a
.Ar seconds
session lifetime.
It is possible to set
.Ar seconds
to default to use the httpd default timeout of 2 hours.
.El
.El
.Sh TYPES
Configure the supported media types.
.Xr httpd 8
will set the
.Ar Content-Type
of the response header based on the file extension listed in the
.Ic types
section.
If not specified,
.Xr httpd 8
will use built-in media types for
.Ar text/css ,
.Ar text/html ,
.Ar text/plain ,
.Ar image/gif ,
.Ar image/png ,
.Ar image/jpeg ,
.Ar image/svg+xml ,
and
.Ar application/javascript .
.Pp
The
.Ic types
section must include one or more lines of the following syntax,
enclosed in curly braces:
.Bl -tag -width Ds
.It Ar type/subtype Ar name Op Ar name ...
Set the media
.Ar type
and
.Ar subtype
to the specified extension
.Ar name .
One or more names can be specified per line.
Each line may end with an optional semicolon.
.It Ic include Ar file
Include types definitions from an external file, for example
.Pa /usr/share/misc/mime.types .
.El
.Sh FILES
.Bl -tag -width /etc/examples/httpd.conf -compact
.It Pa /etc/examples/httpd.conf
Example configuration file.
.El
.Sh EXAMPLES
Example configuration files for
.Nm
and
.Xr acme-client 1
are provided in
.Pa /etc/examples/httpd.conf
and
.Pa /etc/examples/acme-client.conf .
.Pp
The following example will start one server that is pre-forked two
times and is listening on all local IP addresses.
It additionally defines some media types overriding the defaults.
.Bd -literal -offset indent
prefork 2

server "default" {
	listen on * port 80
}

types {
	text/css		css
	text/html		html htm
	text/plain		txt
	image/gif		gif
	image/jpeg		jpeg jpg
	image/png		png
	application/javascript	js
	application/xml		xml
}
.Ed
.Pp
The server can also be configured to only listen on the primary IP
address of the network interface that is a member of the
.Qq egress
group.
.Bd -literal -offset indent
server "default" {
	listen on egress port 80
}
.Ed
.Pp
Multiple servers can be configured to support hosting of different domains.
If the same address is repeated multiple times in the
.Ic listen on
statement,
the server will be matched based on the requested host name.
.Bd -literal -offset indent
server "www.example.com" {
	alias "example.com"
	listen on * port 80
	listen on * tls port 443
	root "/htdocs/www.example.com"
}

server "www.a.example.com" {
	listen on 203.0.113.1 port 80
	root "/htdocs/www.a.example.com"
}

server "www.b.example.com" {
	listen on 203.0.113.1 port 80
	root "/htdocs/www.b.example.com"
}

server "intranet.example.com" {
	listen on 10.0.0.1 port 80
	root "/htdocs/intranet.example.com"
}
.Ed
.Pp
Simple redirections can be configured with the
.Ic block
directive:
.Bd -literal -offset indent
server "example.com" {
	listen on 10.0.0.1 port 80
	listen on 10.0.0.1 tls port 443
	block return 301 "$REQUEST_SCHEME://www.example.com$REQUEST_URI"
}

server "www.example.com" {
	listen on 10.0.0.1 port 80
	listen on 10.0.0.1 tls port 443
}
.Ed
.Pp
The request can also be rewritten with the
.Ic request rewrite
directive:
.Bd -literal -offset indent
server "example.com" {
	listen on * port 80
	location match "/old/(.*)" {
		request rewrite "/new/%1"
	}
}
.Ed
.Sh SEE ALSO
.Xr htpasswd 1 ,
.Xr patterns 7 ,
.Xr httpd 8 ,
.Xr ocspcheck 8 ,
.Xr slowcgi 8
.Sh AUTHORS
.An -nosplit
The
.Xr httpd 8
program was written by
.An Reyk Floeter Aq Mt reyk@openbsd.org .