The DNS directive specifies whether the server performs DNS lookups on clients that access the server. When a client connects to your server, the server receives the client’s IP address but not its host name. For example, the server identifies the client as 198.95.251.30, rather than its host name www.a.com. The server will resolve the client’s IP address into a host name for operations like access control, CGI, error reporting, and access logging.
If your server responds to many requests per day, you might or need to stop host name resolution. Limiting resolution can reduce the load on the DNS or NIS (Network Information System) server.
Syntax
DNS [on|off]
Default
DNS host name resolution is off as a default
Example
DNS on