Tutorial How do I check if my mail server is blacklisted?


Staff member
Apr 27, 2015
Houston, TX
cPanel Access Level
DataCenter Provider
cPanelResources submitted a new resource:

How do I check if my mail server is blacklisted? - Insight on how to check if your mail server is blacklisted.


There are many instances in which external mail servers may block mail from your server, resulting in outgoing mail attempts being rejected with a bounce-back error.

Typically, this issue is caused by your server's sending IP or domain being listed in an existing RBL (Realtime Blackhole List). Some providers may also block emails based on the domain or IP's 'sending reputation' being noted as unknown or in poor standing.

This guide will provide insight on...
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Well-Known Member
Aug 21, 2003
La Crosse, WI
cPanel Access Level
Root Administrator
AOL mail is now managed by Yahoo, so I believe the docs on AOL are now outdated. I've found that Yahoo is pretty impossible to work with, and seems to focus primarily on email volumes. If you have a customer send out a newsletter blast, you can be sure that Yahoo will start deferring all your mail for many hours, even if the emails are fully compliant, double-opt in, etc. If Yahoo went away tomorrow, I would not shed a tear.

PRO TIP: Many of us are using the fantastic ConfigServer Firewall (CSF) product. If you are using CSF, be sure to use the "Check for IPs in RBLs" feature in CSF. You can enable it to check all your IPs (or just some) once per hour/day/week and to email you the report. I have our IPs checked once per day, and have a filter built into my email program to trash the successful reports, and to draw attention to the failures (rare, but happens).


Staff member
Apr 11, 2011
Hi @sneader,

Thanks for the report!

I've opened an internal case to have this tutorial updated, and I'll send an update here when the changes are published.