What to do if your domain name or mailserver IP is listed in a DNS blacklist somewhere

By , April 22, 2010

You find yourself in a situation where email you send from your domain is being rejected by some remote mail servers with a message that your domain is listed in a DNS based blacklist.

The bounce message will contain a line like this:

550 Service unavailable; [your domain here] blocked using some.domain.rbl

There are two things you need to do in order to restore your mailserver integrity:

1. Secure your mailserver. The reason it’s listed in an RBL is because it’s being used to transmit spam or malware. See: http://www.mail-abuse.com/an_sec3rdparty.html for instructions on how to secure various mailservers against third party relaying.

2. Use openrbl.org to find out which blacklist you are listed in (there are many), and follow their delisting procedures.

DNS based blacklists either list your mailserver’s IP address or your domain name. A careful read of the error message should tell you which one is being listed.

Further Reading: http://en.wikipedia.org/wiki/DNSBL

Leave a Reply