Code: $ echo "look up site ip-address" $ nslookup sub.domain.tld Address: 192.168.0.1 Code: $ echo "then look up domains" $ nslookup 192.168.0.1 192.168.0.1.in-addr.arpa name = domain1.com. 192.168.0.1.in-addr.arpa name = domain2.com. 192.168.0.1.in-addr.arpa name = domain3.com. 192.168.0.1.in-addr.arpa name = domain4.com. [cut] Code: $ echo "total domain records" $ nslookup 192.168.0.1 | wc -l 1234 -- Update: Edited by moderator. If you want to post data as example, post data from your own server and not from third party servers.
Its not really insecure because dns servers are laways there to be queried. But I agree with you that its better to change this behaviour so that only one domain is set in the PTR. I will add this to the bugtracker.
>I will add this to the bugtracker. In ISPConfig-2.2.22 it was fixed - Bugfix: Bugfix for PTR records: only one PTR record per IP address; PTR zones are now created correctly