RBL Checks


Mailborder servers have the ability to evaluate remote servers that connect to your Mailborder server by comparing them to various Realtime Blackhole Lists. (RBL) Servers on these lists are typically to be know spammers, badly misconfigured servers, sources of virus and malware, phishing, and other related threats. Not all RBLs are created equal. Some are better than others. Some are weak, and some are too aggressive. 


Viewing Rejections

Remote servers rejected by your RBLs are logged to the GUI. They can be viewed in the Mailborder Master GUI here:

[ top menu > system > rbl reject log ]

You can also check an IP against multiple RBLs using MX Toolbox


Included RBLs

There are several RBLs that you can enable within the Mailborder Master GUI. These changes will apply to all servers within the Mailborder cluster. (If you have Child servers attached.) To view or edit the RBLs used, go here in your Mailborder Master GUI:

[ top menu > cluster > mail transport settings > realtime blackhole lists ]

We have found the Barracuda RBL to be one of the most reliable free resources. 


Configuration Options

If you wish to change how Mailborder evaluates RBLs or add additional custom RBLs to the system, the instructions can be found in this file:


Do not edit this file directly! It is overwritten during updates. Put any desired changes here:



Command Line Tool

You may also use the command line tool available on any Mailborder server to check if an IP is listed in any particular RBL. Below is an example.

root@mx5:/# mb-rbl-eval b.barracudacentral.org
Status: not listed
Time: 0.04s



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