MySQL – no reverse address mapping

I am getting the following messages in the mysql.log file:

“[Warning] IP address ‘XXX.XXX.XXX.XX’ could not be resolved: no reverse address mapping.”

The reverse address mapping is basically requesting from the DNS, “I have this IP address can you give me a domain name associated with this IP address”. The domain name is needed in the login verification i.e. authentication is based on username and host. The host in this case is not an IP address but a host name.

So for example, if the authentication in the server is myuser@localhost, we need to verify that the person is logged on from localhost.

The person logging in will have an identified IP address but not a domain name, so we need to convert the IP address to a domain name. The domain name is then compared along with the username to verify which entry in the mysql.user table should be used to complete verification.