I posted the following on an exchange forum:
>I am running an exchange 2003 server. Some users have not been receiving mail with the error message "status=deferred (conversation with x.x.x.x) >timed out while sending RCPT TO". Using a packet sniffer I was able to trace the SMTP conversation.
>The conversation carries on ok up until the point my server sends the command "Start mail input; end with <CRLF>.<CRLF>". The external server >responds with an ICMP error message "Type 3: Destination unreachable. Code 3: (Port unreachable)".
>This problem is not specific to a particular sending domain.
The reply to the post was that this was not an exchange problem but a routing error. We have an 1800 series cisco router between the internet and our mail server. Just to be clear - the ICMP error message is sent by a router/server ouside our network.
My question is has anyone experienced this kind of error and how did they resolve it?
