Internal Email intermittently going out to Internet and back

[nala1]

Using Outlook 2003, XP SP2, Exhange 2003, DC is Exchange 2003. Recently upgraded from Exchange 5.5 and Outlook 2000. They use Exchange internally only and have POP accounts for any other email. The user can send 10 emails internally which will be delivered normally, the 11th email will go out to the Internet and back in. The recipient is an internal account. It is obviously a client issue but am unsure where to look. DNS settings, etc. have all been verified. If anyone has any insight please advise.
Thanks

 

[Spirit]

How do you know it goes out to the internet and back?

Is the mail being hosted by a third party?

Iain

 

[nala1]

Yes. It is hosted by a third party. If we look at the full header of the email we can see that path the message took.

 

[fuego007]

I'm not sure that it's obviously a client issue. Have you modified the client configuration so that it is connecting only to your Exchange server? Try this and see what happens. If the 11th message still goes out and back, it's your server. If no messages go out it's the client. The only explanation I can think of in that instance is that the client is having difficulty communicating with the Exchange server and is sending the message by the next available means.

When all else fails, READ THE DAMN BOOK!

 

[Spirit]

I'd be interested to see if the client has a DNS entry for the external address (ie. the ISP) which then forwards the mail to the server.

For some reason the client seems to have its own smtp engine?

Dunno clutching at straws!!!