| Variable | IP_FILTER_RDNS | |
| Introduced Version | 1.37 | |
| Description | IP filter for filtering which IP addresses may be queried with the rdns() function. | |
| Default | | |
IP filter for filtering which IP addresses may be queried with the
rdns() function.
The syntax of the IP address list is a sequence, separated 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).
For example, here we deny RDNS queries on the CIDR block
192.168.0.0/16 and allow all others:
ini
IP_FILTER_RDNS=deny 192.168.0.0/16; allow all