Paul, Yes, we are running Exchange 2003. Thanks for the tip! Javier -----Original Message----- From: MSU Network Administrators Group [mailto:[log in to unmask]]On Behalf Of Paul Reed Sent: Wednesday, December 22, 2004 2:53 PM To: [log in to unmask] Subject: Re: [MSUNAG] Mail question If you are using Exchange Server 2003 (this may also work with earlier versions), you can check the SMTP connection limit by starting the Exchange System Manager and drilling down this path: Administrative Groups First Administrative Group Servers [your server name] Protocols SMTP Right-click on "Default SMTP Virtual Server" and choose Properties. On the General tab there is a check box next to "Limit number of connections to:". This is not selected in a default Exchange 2003 install. If your server has a limit set here, you may want to find out why it was limited before you change it. Paul Reed Chemistry ________________________________ From: MSU Network Administrators Group [mailto:[log in to unmask]] On Behalf Of Javier Ornelas Sent: Wednesday, December 22, 2004 2:20 PM To: [log in to unmask] Subject: [MSUNAG] Mail question Periodically, I receive calls from our users (on our Exchange Server) who say that Mail.msu.edu users are trying to e-mail them, but are receiving errors such as: This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: [log in to unmask] SMTP error from remote mailer after initial connection: host ht.msu.edu [35.9.86.5]: 554 <sys09.mail.msu.edu[35.9.75.109]>: Client host rejected: too many connections Can someone help shed some light on what is causing these errors? Is there something I need to change on our Exchange Server? As I said, it is only periodically. Most of the time, there is no problem. Thanks, Javier Ornelas