Only scan mail from external networks through mailscanner

[Norbert Schmidt]

_Hi everybody,

our current setup is using a gateway mailserver that is receiving
external mail and mail from our internal networks (like mail from the
datacenter) and routes them to our mailscanner servers.
As there are a lot of time critical alert mails comming from the
datacenter  I am looking for a way to not scan them on the mailscanners
but rather directly send them to the internal groupware servers.
We are using a postfix setup, thus we are using the header_checks to put
the mail into the hold queue.
mailscanner1:~# cat /etc/postfix/header_checks
/^Received:.by.mailscanner/     IGNORE
/^Received:/ HOLD

I've tried to add this line to the header_checks:
/^Received:.*\.ourdomain\.com/       DUNNO

Which worked somehow to good, as all mail went around the mailscanner
(our gateway servers are using: mail1.ourdomain.com and mail2.ourdomain.com)

I was thinking of a line like:  If IP in header is not one of mine then HOLD

Do you have any idea on how this could be aquired or do you have a
better way to solve this??

Regards

Norbert
_