Configure LiteSpeed Web Server¶

Note

Most of the configuration documentation for LiteSpeed Web Server has not been migrated from our Wiki yet. Please visit the wiki if you don't find what you are looking for below.

Apache-Style Directives¶

These directives can be used within Apache configuration files, but they may be LiteSpeed-specific (i.e. not recognized by Apache), in which case they must be contained within <IfModule litespeed>/</IfModule> tags.

AllowBlockedUrl¶

By default, LiteSpeed prohibits access to some hidden files with extensions like .hta, .git, and .svn. This is a LiteSpeed security feature which does not exist in Apache. Apache may rely on an additional rewrite rule to block such files.

If you need to allow access to these file names for a single vhost (for example, you might want to proxy requests to OpenResty with a rewrite rule in the File Manager function), the AllowBlockedUrl directive can be placed into the Apache configuration for that vhost. AllowBlockedUrl on allows prohibited files to be accessed.

Example

Allow blocked URLs:

<IfModule litespeed>
AllowBlockedUrl on
</IfModule>

ForceSecureCookie¶

LiteSpeed doesn't support Apache's header edit directive, and so the following Apache directive won't work on LiteSpeed:

Header always edit Set-Cookie (.*) "$1;HTTPOnly;Secure;SameSite=none"

The ForceSecureCookie directive may be used to enforce secure, SameSite, and httponly cookie attributes. It can be set in the Apache config file at the server or virtual-host level, or in the .htaccess of the document root directory.

ForceSecureCookie accepts the following values in any order:

off
on or secure
httponly
same_site_lax or lax
same_site_strict or strict
same_site_none

Tips

You can combine same_site_xxxx values with secure and httponly.
LiteSpeed Web Server automatically adds a secure flag when serving traffic over HTTPS, so it is not necessary to add it with a directive.

Examples

To enforce the secure attribute only:

<IfModule LiteSpeed>
ForceSecureCookie secure
</IfModule>

To enforce secure; SameSite=none:

<IfModule LiteSpeed>
ForceSecureCookie secure same_site_none
</IfModule>

To enforce SameSite=strict only:

<IfModule LiteSpeed>
ForceSecureCookie strict
</IfModule>

or

<IfModule LiteSpeed>
ForceSecureCookie same_site_strict
</IfModule>

LogCompressArchive¶

The LogCompressArchive on|off directive is to turn on or off the access log compression archive. This directive may only be set at the server level, and it cannot be used in Apache virtual host configurations.

LogKeepDays¶

The LogKeepDays <N> directive controls how many days to keep the access log. This directive may only be set at the server level, and it cannot be used in Apache virtual host configurations.

LogRotationSize¶

The LogRotationSize <size> directive controls how frequently the access log should be rotated. In other words, once the log reaches the specified size in bytes, the contents will be copied to a backup file and a new log will be started.

This directive may only be set at the server level, and it cannot be used in Apache virtual host configuration.

Tips

LogRotationSize needs to be set prior to defining CustomLog. Once LogRotationSize is set, all subsequent CustomLog configurations will follow the specified size limit.
You can add K, M, or G to the size, to signify kilo-, mega-, and gigabytes respectively. Use a value of 0 to disable the log rotation.

Examples

Disable log rotation:

<IfModule litespeed>
LogRotationSize 0
</IfModule>

Rotate logs after they reach 10MB:

<IfModule litespeed>
LogRotationSize 10M
</IfModule>

MaxReqBodySize¶

Use MaxReqBodySize at the virtual-host level to specify the maximum size of an HTTP request body.

Example

<IfModule LiteSpeed>
MaxReqBodySize 1024M
</IfModule>

MaxDynRespSize¶

Use MaxDynRespSize at the virtual-host level to specify the maximum body size of a dynamically generated response.

Example

<IfModule LiteSpeed>
MaxDynRespSize 1024M
</IfModule>

UniqueId¶

The UniqueId on|off directive is used to create a unique identifier for requests, similar to the Apache mod_unique_id directive. UniqueID is disabled by default.

This directive may be set at the server level, the virtual-host level or in the document root's .htaccess file.

Example

Enable UniqueID:

<IfModule litespeed>
UniqueId on
</IfModule>

Environment Variables¶

The following special environment variables may be used in rewrite rules to control LiteSpeed Web Server features:

blockbot¶

Set the blockbot environment variable to 1 when you are under attack. This will drop the connection.

Examples

Drop the connection for any request from user-agent BUbiNG:

RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} "BUbiNG"
RewriteRule .* - [E=blockbot:1]

Drop the connection for any request for xmlrpc.php:

RewriteRule ^/xmlrpc.php - [E=blockbot:1]

(Don't use this rule at the server level, or it will impact requests globally. Only use a rule like this for the specific virtual host that is under attack.)

cache-ctrl/cache-control¶

The cache-control or cache-ctrl environment variable allows you to modify the server's page cache policy, enable, or disable cache.

Examples

Rewriterule ^/special_cachable_url$ - [E=Cache-ctrl:max-ages=30]

Rewriterule ^/non-cacheable-url$ - [E=Cache-control:no-cache]

For more details on how to use cache-control, please see the LSCache Without a Plugin documentation.

dontlog¶

When set to any value, dontlog prevents access logging.

Example

RewriteRule \.gif - [E=dontlog:1]

FRONTEND_CDN¶

Use the FRONTEND_CDN environment variable to block direct access from all IP addresses, while allowing exceptions for traffic that is passed through one or more specified CDNs.

Traffic attempting to connect from an origin server IP address will be rejected with a 403 error.

Possible CDN values are QUIC.cloud (QC) and Cloudflare (CF).

Example

RewriteCond %{ENV:FRONTEND_CDN} !"QC|CF" [NC]
RewriteRule .* - [F,L]

If FRONTEND_CDN does not match QC or CF then forbid this request.

This method is useful for servers where only a small number of its virtual hosts need to be restricted to CDN access only.

Tip

For servers where you want to restrict all of the virtual hosts to CDN access, it's better to just use your server firewall to restrict access to ports 80 and 443.

HTTP-Prio¶

Sets the HTTP priority (RFC 9218) for HTTP2 and HTTP3 streams.

Value range: 0 (highest) - 7 (lowest). An optional i suffix can be added to indicate incremental (meaning the HTTP response can be processed incrementally).

Examples

E=http-prio:1

E=HTTP-Prio:3i

noabort¶

This flag prevents the server from killing external application processes while they are still running.

Example

RewriteRule ^script_url$ - [E=noabort:1]

noantiddos¶

The noantiddos environment variable lets you disable anti-ddos for the current request. It can be used in SetEnv / SetEnvIf statements or rewrite rules. Introduced in LSWS v6.3.1 build 3.

Example

<IfModule LiteSpeed>
    SetEnv noantiddos
</IfModule>

no-brotli¶

Brotli is a compression algorithm which, much like gzip/deflate, reduces both file size and page load time. Brotli compression is enabled by default for secure static pages and non-ESI dynamic pages.

Brotli cannot be disabled server-wide, but it may be disabled on a per account or per domain basis through Apache configuration and .htaccess files.

Add the following snippet:

<IfModule LiteSpeed>
    SetEnv no-brotli
</IfModule>

A Graceful Restart is required if this snippet is added to an Apache configuration file, but it is not necessary when adding to .htaccess.

no-gzip¶

When set to any non-zero value, no-gzip instructs the server not to use GZIP compression for this request.

Example

RewriteRule \.css - [E=no-gzip:1]

no-gzip:0 has no effect.

nokeepalive¶

When set to any value, nokeepalive closes the client's connection after finishing this request.

Example

RewriteRule .* - [E=nokeepalive:1]

no-lscache¶

As of LSWS v6.3, the no-lscache environment variable lets you disable LSCache for the current request. It can be used in SetEnv / SetEnvIf statements or rewrite rules.

Examples

RewriteRule .* - [E=no-lscache:1]

<IfModule LiteSpeed>
    SetEnv no-lscache
</IfModule>

Proxy-Host¶

Proxy-Host modifies the proxy request Host header value.

Example

A web site whose domain name is www.example.com sends a proxy request to the backend, which is a web server with the name node1. The backend web server requires the domain name to be www.example.com. This is the rewrite rule which enforces that:

RewriteRule ^(.*)$ http://node1/$1 [P,E=Proxy-Host:www.example.com]

wait-req-full-body¶

When LiteSpeed Web Server processes a request, it usually passes the request to the backend (PHP) without waiting for the full request body to complete. Usually, this is not a problem, but it can be an issue if the script needs the whole request body to work properly.

The wait-req-full-body environment variable instructs the server to wait until the full request body completes before passing the request to the backend.

Example

RewriteRule ^(.*)$ - [E=wait-req-full-body:1]