SMTP not working

Folks,
Just installed new Exchange2K3 with sp2 and ISA 2004 with sp1 on 2 seperate DC's. The MX record and all other things are all ok. The mail server publishing rule is working ok on ISA. I can receive some mails but some cant. Also the mails i dont receive is not bouncing back to the sender as well. OS is windows 2003 fully patched.


Domain name is MYDUC.COM. any one with any ideas what should i start looking for.

TIA
Pankaj




Other related posts: