Example: HostnameLookups on
Since: Apache 1.1
This directive specifies whether and how IP addresses of clients
are resolved to their corresponding host names via reverse
DNS lookups, so that clients can be logged and passed to the
CGI/SSI environment. The argument type can be ``on''
to enable full resolving, ``off'' to disable resolving, or
``double'' to enable double-reverse DNS lookups.
In the latter approach, after a reverse lookup is performed,
an additional forward lookup is carried out on that result. At
least one of the IP addresses in the forward lookup must match
the original address in a double-revers DNS lookup. Regardless
of the setting, when mod_access is used for controlling
access by host name, a double-reverse lookup will be always
performed for security reasons.