A host rule mapping module in a firewall server may receive an update notification from a name server. The update notification may indicate a change to an address associated with a host name of a host machine. In response to receiving the update notification, the host rule mapping module may request a record corresponding to the host name identified in the update notification. The host rule mapping module may receive a contents of the record in response to the request from the name server, and update a firewall rule corresponding to the address identified in the update notification to include the contents of the record.