| Variable | IP_FILTER_RDNS_SERVER | |
| Introduced Version | 1.37 | |
| Description | IP filter for filtering which DNS servers may be specified in the rdns function | |
| Default | ||
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 8.8.8.8 and
1.1.1.1 and deny all others.
IP_FILTER_RDNS_SERVER=allow 8.8.8.8; allow 1.1.1.1; deny all