When sending mail through MS Exchange 200, I keep getting 421 Too many errors on this connection -- closing Any idea???

julien cool

Exchange has a limit on the number of mail messages that can be sent across a single SMTP connection. If you hit this limit, then you'll get this message.

In MS Exchange 2000 (and it seems in SMTP Server coming with IIS), there is a properties panel in the Default SMTP Server named "Messages" where you can tune :

  • size of one message
  • number of mails by connection (default is 20)
  • total size of messages in one session
  • recipients by message
See http://www.microsoft.com/technet/treeview/default.asp?url=/TechNet/prodtechnol/exchange/deploy/depovg/exinfflo.asp for more information.