Relay Stop List (RSL)

What is the RSL?

The RSL is a DNS-based list of mail servers that have relayed third-party spam within the recent past. If you run a mail server, you can use this list to refuse mail from those servers. People often block mail from these "open relay" mail servers on the premise that where some spam has traveled, more is likely to follow.

RSL was created by volunteers, users who wanted a conservative open relay list to use to assist's "nospam" server filters. We are happy to share it with others in the Internet community.

How and when are sites listed?

Sites are listed on RSL only if we received what we believe to be spam from the server and we were able to confirm that it is open to third-party relay.

How and when are sites removed?

Sites are removed from the RSL when you ask us to remove them, or after 90 days.

Can I submit my spam to RSL?

At the moment, no. We choose not to accept end-user submissions because doing so would require greater oversight than we care to apply to RSL.

Can I use RSL on my mail server to refuse mail from these open relays?

Yes. RSL is a DNSBL zone, like the MAPS RBL, SPEWS, etc. The name of the zone is "", and any mail server software that supports DNS-based blocking lists should be able to utilize it.

Can I use RSL via procmail?

Yes. Since you can freely query the RSL zone, you can utilize it within procmail.

What makes RSL different than other relay lists?

Unlike MAPS RSS, it is freely queryable. Unlike ORBL or OsiruSoft, RSL only tests or lists as site after receiving spam from that site. RSL is conservative -- entries expire from the list at 90 days, and we will gladly remove any listing from the RSL upon request.

<< RSL Home | Updated 11/18/01