I currently have an Exchange 2003 server that will not allow users to send an email to anyone with a dash in the email address. ie. email-user@hotmail.com The exchange server kicks back a message that states: Your message did not reach some or all of the intended recipients. Subject: Emails Sent: 12/21/2010 4:37 PM The following recipient(s) cannot be reached: 'email-user@hotmail.com' on 12/21/2010 4:37 PM None of your e-mail accounts could send to this recipient. I recently installed 2003 onto a new server and might have a setting that needs changed. Any help would be appreciated.

Interesting as its a supported format, have you turned on Message Tracking to get a better idea what may be happening? The NDR is also very strange as it does not reference an RFC 1891 or 1893 error code so I am wondering if you have a device (filtering appliance/software) that is scanning mail as it leaves your Exchange Server that might be causing this issue?MVP Exchange Server

Hi, Yes, this email-user@hotmail.com is a supported format. Please use telnet to submit the email and see if the issue persists. If there is any firewall installed on exchange server, please also disable it for testing. http://support.microsoft.com/kb/153119Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT

I get a "550 5.7.1 Unable to relay for emailuser@email-user.com" after putting in RCPT TO: emailuser@email-user.com I think it may be an issue with my firewall or my filtering device. What ports do I need opened besides 25 for outgoing?