Introduced Version1.37


IP filter for filtering which DNS servers may be specified in the rdns function.

The syntax of these list is a sequence, seperated by newlines or ;, of allow or deny actions, along with a CIDR block or all. An IP address is allowed or denied by finding the first match and applying the corresponding action. The all value matches any IP-address (i.e., IPv4 or IPv6).

Note that this only restricts what may be specified - if no server is specified then the system default or the one specified by RDNS_DEFAULT_SERVER will be used irrespective of whether it is blocked by this filter.

For example, here we restrict the server to and and deny all others.

ini files
IP_FILTER_RDNS_SERVER=allow; allow; deny all