Mails Unable to send, but receiving works fine!!

[ash2000in]

Hi All,
I have an Exchange2K on a LAN, and an ISA Server with live-IP configured to send/receive all mails.
At times, the mail-system works fine, but unfortunately, it happens many times that the dont get delivered! All the outgoing mails(excluding those addressed within the scope of the local Exchange addresses) are stuck-up in the "Queue" in their respective SMTP Connectors.
The ISA server is able to ping & resolve the IP addresses of the domain names.
The Exchange is able to receive and deliver mails to the respective mailboxes-which are received from external mail servers(like abc@yahoo.com etc)..which means that there is no need to check the MX Records too!!

I have checked with ISPs and they say there cannot be any problems from thier side since thier DNS Servers are working fine, and even my ISA server is able to resolve addresses!

Please help on how can I resolve this issue! My mails are stuck at the Exchange!

Ash

 

[tfarley]

Is your SMTP connector setup to use DNS or a smart host? Don't use ISA but I have a firewall that runs DNS on it's external interface, and I have to point the SMTP connector to it's internal address as a smart host.

Hope this helps

Tony