DNS Primary or Backup Service Anycast

Check your mail server ip

Use this tool to verify your sending mail server ip on our internal and 3rd party Realtime block lists.

All RBLs ending in .zmfs are internal lists, if your having issues with internal block lists please open a support ticket.

RBLs are used by our Spam Cluster to score incoming / outgoing mail. If you are listed by a list not ending in .rbl.zmfs please contact them for delisting.


We sync and lookup with multiple providers, we cannot remove from their lists only our own.

The following error codes will be displayed based on the filtering systems dicision

Check your mail server logs
2.0.00 - Accepted
2.0.77 - Add Header (Could be Spam)
2.0.78 - Rewrite Subject (Mostlikely Spam)
4.3.00 - Deffered (Greylisting)
4.7.70 - Rejected (High Possibility of Spam)