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.