Webmaster in a Nutshell, 3rd Edition By Robert Eckstein, Stephen Spainhour
Table of Contents
Chapter 18. Apache Configuration
HostNameLookups
HostNameLookups onoffdouble
[ server config , within <VirtualHost> or <Directory>]
Enables whether the server should perform hostname lookups on clients instead of simply recording the IP address in the connection logs. If the double option is specified, the server performs a forward and reverse DNS lookup; this ensures the client hostname maps to its IP, as well as the IP mapping to the DNS name . The default is off.
