How do I whitelist a server or IP address so emails from it do not get scanned on my server?

1. To whitelist an IP address from spam scanning, add an appropriate line to /usr/mailscanner/etc/rules/spam.whitelist.rules. If you have the MS Front-end installed, add it to WHM > MailScanner > Front-End Settings > Server Spam Whitelist instead.

2. To whitelist an IP address from filename or filetype filtering you can add an appropriate line to the filename and filetype rulesets in /usr/mailscanner/etc/rules/:

filetype.rules.rules:
From:   123.123.123.123     /usr/mailscanner/etc/filetype.no.rules.conf

filename.rules.rules:
From:   123.123.123.123     /usr/mailscanner/etc/filename.no.rules.conf

Whitelisting an IP address from virus scanning is not recommended.