XCLIENT: No reverse DNS lookup done if only ADDR is provided

[Michael Kliewe]

Hello,

I'm using the XCLIENT feature. The maschine in front of Postfix hands over the mails to Postfix, and while doing that it gives the original IP address to Postfix via XCLIENT ADDR.

I'm now seeing the following:
The IP address of the original sender is given to Postfix correctly, but the reverse name is always "unknown". During the last days I was searching for the problem, and I found out that chroot might be the problem. But it's not.

I guess the problem is the following: The connection is made from the maschine in front of Postfix, which has a 10.0.xxx.xxx ip address. Doing a reverse lookup results in "unknown". Then the original IP address comes in via XCLIENT ADDR. But it's just the IP address, no NAME or REVERSE_NAME. I guess Postfix now only overwrites the IP, and does not lookup the Reverse DNS Name of that IP address, Postfix leaves "unknown" in place.

Is that correct? Is it possible to tell Postfix to lookup the Reverse DNS name of the IP address which came in via XCLIENT, and then overwrite the "unknown" from the internal IP address?

Is there any solution for this? Or is the only solution that the maschine in front of Postfix has to lookup the Reverse DNS Name and send it to Postfix via NAME or REVERSE_NAME in the XCLIENT command? As far as I know that maschine does not do a reverse DNS lookup on the IP address. I would like Postfix to do that lookup...

Any help welcome
Thanks
Michael