iMail sever on SSN cannot reply to Exch2000 on internal network

[gojoerun]

I have Exchange 2000 sever on the internal newtork and iMail mail server on the SSN. OUr firewall server has been configured to allow mail flow from SSN to Internal. Firewall rules have been verified to work properly. I have a DNS server on the SSN resolving MX record and hosts for internal resources and gateway. My problem is mail flow. I can send mail from Exchange to Imail but I cannot reply or send any mail from imail to Exchange. I know the firewall is set properly. My log file indicates I have a problem with connection (as shown below)


SMTP-(05140011) [X] Connecting socket to service <SMTP> on host (172.30.1.5> using TCP
SMTP-(05140011) [X] using source IP for server.xyz.com [10.10.10.1]
SMTP-(05140011) Connect fail 172.30.1.5 [172.30.1.5]: connection timed out
SMTP-(05140011)requesting c:\IMail\spool\Q66a241f0760.GSC R0 T1
SMTP-(05140011) finished c:\IMail\spool\Q66a241f0760.GSC status=3

Would anyone have any information or suggestions to help troubleshoot ?

Thanks !

Joe