All, Career, Technology

Email – RBL (Realtime Blackhole List(s))

If you manage your email services & you are experiencing a lot of undelivered / returned / “disappearing” outgoing email, although some outgoing messages get through, but incoming email is always delivered just fine, then it is highly likely that your outgoing email server (which may or may not be the same as your incoming one) has been added to an “RBL” (Realtime Blackhole List). RBLs are lists of servers which are believed to be sources of spam. These are maintained by a number of organisations and are one of the first & best ways to limit acceptance of spam by your email systems. If you are responsible for an email server you will almost certainly be using this approach to screen email coming into your organisation already. If you’re not (yet) then you definately need to read on!

1. Checking if your server(s) has / have been “Blackholed”;

The best way to check is to enter your email server’s IP address into an RBL checker service;

http://www.anti-abuse.org
http://www.mxtoolbox.com/blacklists.aspx
http://cqcounter.com/rbl_check/
(Ignore  “blacklist.spambag.org” as its non-operational)

If you find you have been listed by one of the RBLs on these services then go direct to the listing list’s own website and follow their removal / “delisting” procedure.

2. If you want to use an RBL service on your incoming email server then;

Simply find the place where your incoming email server accepts RBL list servers / services & add;

zen.spamhaus.org (The best)
dnsbl.sorbs.net (or safe.dnsbl.sorbs.net if you’re a bit nervous!)
bl.spamcop.net (Be careful, quite aggressive).

So I hope that helps you get the best from / manage RBLs and help clamp down on spam.

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