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HTTPD.CONF(5) File Formats Manual HTTPD.CONF(5)

httpd.conf — HTTP daemon configuration file

httpd.conf is the configuration file for the HTTP daemon, httpd(8).

httpd.conf is divided into the following main sections:

User-defined variables may be defined and used later, simplifying the configuration file.
Global settings for httpd(8).
Listening HTTP web servers.
Media types and extensions.

Within the sections, a host address can be specified by IPv4 address, IPv6 address, interface name, interface group, or DNS hostname. If the address is an interface name, httpd(8) will look up the first IPv4 address and any other IPv4 and IPv6 addresses of the specified network interface. If ‘*’ is given as an address, httpd(8) will listen on all IPv4 and IPv6 addresses. 0.0.0.0 means to listen on all IPv4 addresses and :: all IPv6 addresses. A port can be specified by number or name. The port name to number mappings are found in the file /etc/services; see services(5) for details.

The current line can be extended over multiple lines using a backslash (‘\’). Comments can be put anywhere in the file using a hash mark (‘#’), 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.

Argument names not beginning with a letter, digit, or underscore must be quoted.

Additional configuration files can be included with the include keyword, for example:

include "/etc/httpd.conf.local"

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, directory, log, or root). Macros are not expanded inside quotes.

For example:

ext_ip="10.0.0.1"
server "default" {
	listen on $ext_ip port 80
}

Here are the settings that can be set globally:

directory
Set the chroot(2) directory. If not specified, it defaults to /var/www, the home directory of the www user.
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 TYPES section below. If not specified, the default type is set to application/octet-stream.
directory
Let httpd(8) return custom error documents instead of the built-in ones.

directory is relative to the chroot.

Custom error documents are standalone “.html” files provided in one of the following ways:

  • As HTML files named after the 3-digit HTTP response code they are used for, e.g., 404.html.
  • As a generic template file named err.html which is used for response codes no dedicated file is provided for.

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.

A custom error document may contain the following macros that will be expanded at runtime:

The error message text.
The 3-digit HTTP response code sent to the client.
The server software name of httpd(8).
directory
Specifies the full path of the directory in which log files will be written. If not specified, it defaults to /logs within the chroot(2) directory.
number
Run the specified number of server processes. This increases the performance and prevents delays when connecting to a server. httpd(8) runs 3 server processes by default.

The configured web servers.

Each server section starts with a declaration of the server name:

name {...}
Match the server name using shell globbing rules. This can be an explicit name, www.example.com, or a name including wildcards, *.example.com.
server match name {...}
Match the server name using pattern matching, see patterns(7).

Followed by a block of options enclosed in curly braces:

name
Specify an additional alias name for this server.
alias match name
Like the alias option, but match the name using pattern matching instead of shell globbing rules, see patterns(7).
[no] authenticate [realm] with htpasswd
Authenticate a remote user for realm by checking the credentials against the user authentication file htpasswd. The file name is relative to the chroot and must be readable by the www user. Use the no authenticate directive to disable authentication in a location.
block drop
Drop the connection without sending an error page.
[return code [uri]]
Close the connection and send an error page. If the optional return code is not specified, httpd(8) denies access with a ‘403 Forbidden’ response. The optional uri argument can be used with return codes in the 3xx range to send an HTTP Location header for redirection to a specified URI.

It is possible to rewrite the request to redirect it to a different external location. The uri may contain predefined macros that will be expanded at runtime:

The request path.
The query string of the request.
The URL-encoded query string of the request.
The IP address of the connected client.
The TCP source port of the connected client.
The remote user for HTTP authentication.
The request scheme (http or https).
The request path and optional query string.
The configured IP address of the server.
The configured TCP port of the server.
The name of the server.
The host from the HTTP Host header.
%n
The capture index n of a string that was captured by the enclosing location match option.
option
Set the specified options and limits for HTTP connections. Multiple options may be specified within curly braces. Valid options are:
number
Set the maximum body size in bytes that the client can send to the server. The default value is 1048576 bytes (1M).
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.
request timeout 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).
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).
type/subtype
Set the default media type for the specified location, overwriting the global setting.
option
Set the specified options when serving or accessing directories. Multiple options may be specified within curly braces. Valid options are:
[no] auto index
If no index file is found, automatically generate a directory listing. This is disabled by default.
string
Set the directory index file. If not specified, it defaults to index.html.
Disable the directory index. httpd(8) will neither display nor generate a directory index.
[no] errdocs directory
Overrides or, if the no keyword is given, disables globally defined custom error documents for the current server.
[no] fastcgi [option]
Enable FastCGI instead of serving files. Multiple options may be specified within curly braces. Valid options are:
[tcp] socket [port]
httpd passes HTTP requests to a FastCGI handler listening on the socket socket. The socket can either be a UNIX domain socket or a TCP socket. If the FastCGI handler is listening on a UNIX domain socket, socket is a local path name within the chroot(2) root directory of httpd(8) and defaults to /run/slowcgi.sock. Alternatively if the FastCGI handler is listening on a TCP socket, socket is a hostname or an IP address. If the port is not specified, it defaults to port 9000.
number
Strip 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.
variable value
Sets a variable that will be sent to the FastCGI server. Each statement defines one variable.

The FastCGI handler will be given the following variables by default:

The document root in which the script is located as configured by the root option for the server or location that matches the request.
The revision of the CGI specification used.
Additional HTTP headers the connected client sent in the request, if any.
A variable that is set to "on" when the server has been configured to use TLS. This variable is omitted otherwise.
The path and optional query string as requested by the connected client.
The canonicalized request path, possibly with a slash or directory index file name appended. This is the same as PATH_INFO appended to SCRIPT_NAME.
The virtual URI path to the script.
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.
The absolute, physical path to the script within the chroot(2) directory.
The optional query string of the request. This variable is an empty string if there is no query string in the request.
The IP address of the connected client.
The TCP source port of the connected client.
The remote user when using HTTP authentication.
The HTTP method the connected client used when making the request.
The configured IP address of the server.
The name of the server.
The configured TCP server port of the server.
The revision of the HTTP specification used.
The server software name of httpd(8).
A variable that is set to a comma separated list of TLS client verification features in use (omitted when TLS client verification is not in use).
Enable static gzip compression to save bandwidth.

If gzip encoding is accepted and if the requested file exists with an additional .gz suffix, use the compressed file instead and deliver it with content encoding gzip.

[option]
Enable HTTP Strict Transport Security. Valid options are:
seconds
Set the maximum time in seconds a receiving user agent should regard this host as an HSTS host. The default is one year.
Confirm and authenticate that the site is permitted to be included in a browser's preload list.
Signal to the receiving user agent that this host and all sub domains of the host's domain should be considered HSTS hosts.
address [tls] port number
Set the listen address and port. This statement can be specified multiple times.
[[not] found] path {...}
Specify server configuration rules for a specific location. The path argument will be matched against the request path with shell globbing rules. Optionally, it is also possible to match for found (i.e. accessible) or 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 alias, connection, errdocs, hsts, listen on, location, tcp and tls.
[[not] found] match path {...}
Like the location option, but match the path using pattern matching instead of shell globbing rules, see patterns(7). The pattern may contain captures that can be used in an enclosed block return or request rewrite option.
[no] log [option]
Set the specified logging options. Logging is enabled by default using the standard access and error log files, but can be changed per server or location. Use the no log directive to disable logging of any requests. Multiple options may be specified within curly braces. Valid options are:
name
Set the name of the access log file relative to the log directory. If not specified, it defaults to access.log.
name
Set the name of the error log file relative to the log directory. If not specified, it defaults to error.log.
style
Set the logging style. The style can be common, combined, forwarded or connection. The styles common and combined write a log entry after each request similar to the standard Apache and nginx access log formats. The style forwarded extends the style combined by appending two fields containing the values of the headers X-Forwarded-For and X-Forwarded-Port. The style connection writes a summarized log entry after each connection, that can have multiple requests, similar to the format that is used by relayd(8). If not specified, the default is common.
[no] syslog
Enable or disable logging to syslog(3) instead of the log files.
Disable any previous block in a location.
option
Configure the options for the request path. Multiple options may be specified within curly braces. Valid options are:
[no] rewrite path
Enable or disable rewriting of the request. Unlike the redirection with block return, this will change the request path internally before httpd makes a final decision about the matching location. The path argument may contain predefined macros that will be expanded at runtime. See the block return option for the list of supported macros.
number
Strip number path components from the beginning of the request path before looking up the stripped-down path at the document root.
directory
Configure the document root of the server. The directory is a pathname within the chroot(2) root directory of httpd. If not specified, it defaults to /htdocs.
option
Enable or disable the specified TCP/IP options; see tcp(4) and ip(4) for more information about the options. Multiple options may be specified within curly braces. Valid options are:
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 kern.somaxconn sysctl(8) variable.
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.
number
Change the default time-to-live value in the IP headers.
[no] nodelay
Enable the TCP NODELAY option for this connection. This is recommended to avoid delays in the data stream.
[no] sack
Use selective acknowledgements for this connection.
socket buffer number
Set the socket-level buffer size for input and output for this connection. This will affect the TCP window size.
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:
file
Specify the certificate to use for this server. The file should contain a PEM encoded certificate. The default is /etc/ssl/server.crt.
string
Specify the TLS cipher string. If not specified, the default value "HIGH:!aNULL" will be used (strong crypto cipher suites without anonymous DH). See the CIPHERS section of openssl(1) for information about SSL/TLS cipher suites and preference lists.
cafile [crl crlfile] [optional]
Require (or, if optional is specified, request but do not require) TLS client certificates whose authenticity can be verified against the CA certificate(s) in cafile in order to proceed beyond the TLS handshake. With crl specified, additionally require that no certificate in the client chain be listed as revoked in the CRL(s) in crlfile. CA certificates and CRLs should be PEM encoded.
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.
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 tls_config_set_ecdhecurves(3) for further details.
file
Specify the private key to use for this server. The file should contain a PEM encoded private key and reside outside of the chroot(2) root directory of httpd. The default is /etc/ssl/private/server.key.
file
Specify an OCSP response to be stapled during TLS handshakes with this server. The file should contain a DER-format OCSP response retrieved from an OCSP server for the certificate in use, and can be created using ocspcheck(8). The path to file is not relative to the chroot. If the OCSP response in file is empty, OCSP stapling will not be used. The default is to not use OCSP stapling.
string
Specify the TLS protocols to enable for this server. Refer to the tls_config_parse_protocols(3) function for valid protocol string values. By default, TLSv1.3 and TLSv1.2 will be used.
seconds
Enable TLS session tickets with a seconds session lifetime. It is possible to set seconds to default to use the httpd default timeout of 2 hours.

Configure the supported media types. httpd(8) will set the Content-Type of the response header based on the file extension listed in the types section. If not specified, httpd(8) will use built-in media types for text/css, text/html, text/plain, image/gif, image/png, image/jpeg, image/svg+xml, and application/javascript.

The types section must include one or more lines of the following syntax, enclosed in curly braces:

type/subtype name [name ...]
Set the media type and subtype to the specified extension name. One or more names can be specified per line. Each line may end with an optional semicolon. Later lines overwrite earlier lines.
file
Include types definitions from an external file, for example /usr/share/misc/mime.types.

/etc/examples/httpd.conf
Example configuration file.

Example configuration files for httpd.conf and acme-client(1) are provided in /etc/examples/httpd.conf and /etc/examples/acme-client.conf.

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.

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
}

The server can also be configured to only listen on the primary IP address of the network interface that is a member of the "egress" group.

server "default" {
	listen on egress port 80
}

Multiple servers can be configured to support hosting of different domains. If the same address is repeated multiple times in the listen on statement, the server will be matched based on the requested host name.

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"
}

Simple redirections can be configured with the block directive:

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
}

The request can also be rewritten with the request rewrite directive:

server "example.com" {
	listen on * port 80
	location match "/old/(.*)" {
		request rewrite "/new/%1"
	}
}

htpasswd(1), patterns(7), httpd(8), ocspcheck(8), slowcgi(8)

The httpd(8) program was written by Reyk Floeter <reyk@openbsd.org>.

September 2, 2022 OpenBSD-7.3