1. 421 Connection Limit Reached - HELP!!!
My company has been experiencing the following problem for the past month or
We're running Exchange 5.5 SP4 on Windows NT 4.0 SP6a; open relay is closed.
Every so often, the server's ability to send/receive Internet e-mail slows
to a crawl. Mail eventually goes through, but it takes much longer than it
should. Internal mail is unaffected. Performing a telnet to port 25
produces the "421 <server name> connection limit reached" error.
Additionally, remote users connecting via Outlook Express receive a similar
Stopped and restarted the IMS, rebooted the server. No effect.
I tried raising the connection limit in the IMC properties. No effect.
Microsoft told us to remove the "fixup protocol smtp 25" line from our Cisco
Applied a Hotfix (don't have the number handy), per Microsoft. No effect.
Upon inspection of the IMC logs early on in the process, I noticed that
there were TONS of incoming connections from various computers in the
Brazilian domain (.br - 200.x.x.x IP range). MS initially said that it was
nothing, but later told us to have our Cisco guys create access lists in the
Pix denying those IPs. We blocked the subsets that appeared in the logs
(200.145.x.x., 200.167.x.x, for example), but we're still experiencing the
The problem is very sporadic and our ISP doesn't notice any unusual activity
while the problem is occurring (indeed, only Exchange is affected), but I'm
thinking that it's some kind of attack since the Brazilian domains only
appear when this problem is occurring. I'm hesitant to block the entire
200.x.x.x range, but I will if it stops this problem.
2. X.400 Connector only sends mail on startup...
3. Please help me ..about connection limit reached
4. How to add a Conference room as a Resource when scheduling meetings?
5. NT 4 Server. Exchange Fax.
6. Help: OWA limits number of connections?
7. Can't install E2K Upgrade as new installation
8. Help needed - win 2000 iis virtual SMTP server routing to exchang 5.5
9. Exchang Help Needed
10. PLEASE HELP - Trying to update user Home address field on Exchang e Server
11. Help Creating New Domain with Exchang 2000
12. Adding User but it is not making exchang mailbox HELP