#### IP Lookup Filter

IP Lookup is a filter that checks the IP address of a comment's author on shared lists called DNS-based Blackhole List (DNSBL) (also known as Real-time Blackhole List (RBL)). By default, the filter uses the following servers: `sbl-xbl.spamhaus.org` and `bsb.spamlookup.net`. You can find a list of existing servers on this page.

You can add as many servers as you want, separated by commas. Don't forget to click on Save to take your modifications into account.