Strip "Recieved" headers via Postfix

[psarhjinian]

We're starting to see hosts on the internet block mail from our mailserver based on entries in the SMTP header's Received: fields on the grounds that certain outbound IPs have sent infected messages to the internet at some point in time.

The problem is that we have a large number of mobile contractors, and they're often on someone else's network, and that person's network shows up as a Received: entry. And sometimes that IP's presence in the list of Received: headers is enough to get a message blocked.

I can get around this by having our contractors establish a VPN connection, but that will get expensive quickly. I can also have debates with other mail server admins handling these devices, but that takes days to resolve.

What I would like to do is have Postfix strip out Received headers. I've found instructions to do this, but I'd like to know if anyone else has done this and if it's "safe" to do with Zimbra's Postfix.

[uxbod]

Perhaps by making a modification :- http://www.zimbra.com/forums/install...querading.html

[psarhjinian]

I looked at masquerading, but it didn't do what I wanted because it wouldn't strip the Received headers of prior SMTP deliveries.

The last post in that message is similar to what I want to do, but it's still just rewriting the header, rather than excising it altogether. It is pretty close (they're using REPLACE; I'd intended to use IGNORE) to what I want to do, and should work as long as no one I try to send mail to is filtering on domain names in the Received header in the manner I see them do with IPs now.

I'll try and see what happens. It's nice to see someone else has done it.

It would be nice to see this as a config option, what with spam filtering becoming so zealous that this is now necessary.

[uxbod]

Then please file a RFE

[psarhjinian]

I have been looking at this but I can't figure out what to modify. Changing either

• /opt/zimbra/conf/postfix_header_checks
• /opt/zimbra/conf/postfix_header_checks.in

sees the changes discarded when zmmtaconfigctl is restarted.