I have Cisco PIX firewall UR & FO with OS 7.2(2), and this PIX has one DMZ zone for Connecting the Public IF for the VPN Concentrator, the outside interface is connected to the outside network "Internet Router", the Inside IF is connected to Net Screen FW 20
PIX INSIDE has the same subnet with Net Screen untrust
The NS has one DMZ for connecting the private IF for the VPN Concentrator, and the second DMZ for connecting SMTP Server "Front".
The trust IF for the NS is connected to the Core siwtches "6509", the Exchange Server is connected to the core switches.
Everything works fine, we can send and receive mails.
The customer needs to move the front server from the NS DMZ to a new DMZ at the PIX.
After we moved the front server to the PIX DMZ, we can receive mails normally, but the problem is when sending mails - failed.
Everything is permitted at the NS trust interface, and the same thing done at the PIX inside.
No routing or natting problems, i think it is SMTP errors
ESMTP inspection is done at the PIX.
Thanks in advance