Manual:$wgDBserver/hu

Details
Database host name or IP address. Found in.

If you are using MySQL on a non-standard port, you can use the "hostname:port" syntax, for example. Note that using a port number when you specify  as the host name will have no effect, as MySQL will connect through a socket instead. If the MySQL server is on the same server and you want to connect through a socket in a non-standard location, you can use the "localhost:socket" location, for example.

Tip: Use IP addresses where possible to avoid the overhead of a DNS lookup for every single connection to the wiki. will be faster than