Cronjob an RBL Check

There’s a fantastic website that you can run curl to fetch a list of the blacklist and simple mail checks to ensure any of your servers that send mail aren’t blacklisted.

Create a new file at /etc/cron.daily/rblchecker and place these contents in:

#!/bin/sh
/usr/bin/curl checkrbl.com

Then make it executable chmod +x /etc/cron.daily/rblchecker and it’ll run. You may need to adjust the path to curl. When it runs, you’ll get the following output:

===================================
CheckRBL.com - Comments, suggestions and bug reports: feedback@checkrbl.com
IP CHECK FOR 85.159.213.127
===================================
RBL Checks

not listed in Backscatterer
not listed in Barracuda Central
not listed in McAfee
not listed in SenderScore
not listed in SpamCop
not listed in SpamHaus PBL
not listed in SpamHaus SBL
not listed in SpamHaus XBL
not listed in UCE-Protect

Reverse Record Check
Reverse Record present: aeson.ssx.io
SMTP port check
Connected to 85.159.213.127 on port 25, mail banner says: aeson.ssx.io.

Found ‘A’ Record for aeson.ssx.io: 85.159.213.127

DNS ‘A’ record for aeson.ssx.io matches the given IP 85.159.213.127
Results
GOOD: Reverse record matches SMTP banner, 3-way mailcheck PASS.