In MailScanner Configuration > "Maximum Archive Depth = ", enter
the name of a ruleset (e.g. %rules-dir%/archive.rules). Then save
Create a file with that name in the /usr/mailscanner/etc/rules/
directory. This file should contain the following (replace domain.com
with the domain you wish to skip scanning within archives for):
To: *@domain.com 0
FromOrTo: default 3
You must include the default line so MailScanner will know what to do with domains that are not specified.