SMTP Connectivity Problem

[Muthu]

We have two Exchange Server connected across WAN and communicates through
SMTP.

Some times SMTP connection fails and some times it works fine, when I telnet
the other server with port 25 some times it succeeds and some time fails.

I want to know if there is any utility which will find where the port is
getting blocked across the network. Some thing like trace route with tcp
port.

Any Help would be much appreciated.

Tks,
Muthu

 

[Guest]

What are the exact errors you are getting when it fails? it may help some.
Also you should try telnetting to the IP address of the exchange server to
rule out the possibility of a local name resolution problem. For example, if
the other exchange computer is reciving dynamic DNS information, you could
possible have an incorrectly cached 'A' record for the server until all DNS
servers are updated and your local cache expires.