gateway mode - rewrites IP/hostname?

[perler]

I used to have a simple ubuntu box as a gateway for my VMs but decided to try something more fancy. Everything is working fine so far, but I found that zentyal is "somehow" rewriting the IPs/hostnames of the LAN VMs to the IP of the gateway machine. example:

a port25 report shows, that a mail sent from a LAN VM has been received by the gateway machine:

Code: [Select]

Received: from gw.domain.com ([1.2.3.4] helo=vm.domain.com)
on my old gateway this line simply read:

Code: [Select]

Received: from vm.domain.com
as the helo is identical to the IP of the sender

is there a way to change this behaviour? I would like to have the gateway behave as transparent as possible.