Hi, One of our exchange server is not able to deliver a mail to another mailserver. The following sequence takes place in the smtp log: 1. The connection is opened with the other server 2. The server identifies itself "EHLO - mail.mailserver.be 0 0 4 0 63 SMTP - - - -" 3. The other server replies "250-mail.othermailserver.com 0 0 25 0 94 SMTP" 4. "MAIL - FROM:<Administrator@othermailserver.be>+SIZE=2208 0 0 4 0 94 SMTP" 5. "250+sender+<Administrator@mailserver.be>+ok 0 0 39 0 125 SMTP - - - -" 6. "RCPT - TO:<administrator@othermailserver.com> 0 0 4 0 125 SMTP" 7. "250+recipient+<administrator@othermailserver.com>+ok" 8. "DATA - - 0 0 4 0 469 SMTP" Our mailserver sends the data of the mail 9. The other server replies with the following message: "354+go+ahead 0 0 12 0 500 SMTP" 10. All communication stops, there is no "250+ok:++Message+2944586+accepted" 11. Eventually the server times out and tries again. Wireshark confirms what I've seen in the smtp logs. I have no issues sending the mail to other domains. I have undertaken the following actions on the server so far: Installed every update available for Windows + every update for the exchange server. I have also installed every driver update available.

Hi Ok, you can send to everyone excepts one domain? Maybe they have problem? Try to give them a call?Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

They are looking in to it. I posted this message in the meantime whilst waiting for their reply.

Ok, keep us updated :)Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

The client hasn't had any more issues since the driver update. I believe that the nic driver update was the key to solving the problem.

Great to hear! Thanks for sharing, don't forget to set the thread to solved :)Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog