when a send an email to any yahoo mail address, mi Exch 2003 server don't send it, but to any other type of email (hotmail, gmail, etc) it works ok and send the message, How I can solve this problem?

Do you get a NDR back? If so, can you post exactly what it says? If not, are they in the outbound queue? There should be a reason listed in the queue for those messages.Alternatively, enable SMTP logging and post what it says:http://support.microsoft.com/kb/821910

Are you greylisted? I know that tends to happen with Yahoo.Mark Morowczynski|MCT| MCSE 2003:Messaging, Security|MCITP:ES, SA,EA|MCTS:Windows Mobile Admin|Security+|http://almostdailytech.com

Please post the detaill Non Dilvery Report here.

Enable the Logging for SMTP virtual server Start Exchange System Manager. Expand Servers\Your_ Server_Name \Protocols\SMTP . Right-click SMTP Virtual Server , and then click Properties . On the General tab, click to select the Enable Logging check box. In the Active Log Format list, click W3C Extended Log File Format . Click Properties . On the General Properties tab, click the log schedule that you want to use under New log schedule . In the Log file directory box, type the path where you want to keep the log files. Click the Advanced tab, and then click to select the check box next to each extended logging option in the Extended logging options list that you want to track. Click Apply , and then click OK to close Logging Properties . Click Apply , and then click OK to save your settings and close SMTP Virtual Server Properties . Send couple of mails to yahoo.com domain and then check in the above logs to see what is the causeVinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|