Syntax: server_name name ...;
Default:    
server_name "";
Context:    server

Sets names of a virtual server, for example:

server {
    server_name example.com www.example.com;
}

The first name becomes the primary server name.

Server names can include an asterisk (*) replacing the first or last part of a name:

server {
    server_name example.com *.example.com www.example.*;
}

Such names are called wildcard names.

The first two of the names mentioned above can be combined in one:

server {
    server_name .example.com;
}

It is also possible to use regular expressions in server names, preceding the name with a tilde (~):

server {
    server_name www.example.com ~^www\d+\.example\.com$;
}

Regular expressions can contain captures (0.7.40) that can later be used in other directives:

server {
    server_name ~^(www\.)?(.+)$;

    location / {
        root /sites/$2;
    }
}

server {
    server_name _;

    location / {
        root /sites/default;
    }
}

Named captures in regular expressions create variables (0.8.25) that can later be used in other directives:

server {
    server_name ~^(www\.)?(?<domain>.+)$;

    location / {
        root /sites/$domain;
    }
}

server {
    server_name _;

    location / {
        root /sites/default;
    }
}

If the directive’s parameter is set to $hostname (0.9.4), the machine’s hostname is inserted.

It is also possible to specify an empty server name (0.7.11):

server {
    server_name www.example.com "";
}

It allows this server to process requests without the Host header field — instead of the default server — for the given address:port pair. This is the default setting.

During searching for a virtual server by name, if the name matches more than one of the specified variants, (e.g. both a wildcard name and regular expression match), the first matching variant will be chosen, in the following order of priority:

• the exact name
• the longest wildcard name starting with an asterisk, e.g. *.example.com
• the longest wildcard name ending with an asterisk, e.g. mail.*
• the first matching regular expression (in order of appearance in the configuration file)