Since LISTSERV(R) is not an SMTP application, then I would not expect
to find any problem w/i its log.

The only other question about the you abstracted here is if all of the
IP addresses (or networks) were the same?  Also, can you telnet into
port 25 and do HELP ?

Strangely a google search on "host connection threshold exceeded" came
out empty.


On 9/13/2010 11:08 AM, Rick Scheller wrote:
> We are using ListServ 15.5 and are relaying out to a group of 5 smtp server at our enterprise level.  The logs on these servers are filled with:
>
> 09-13-2010.00:10:04 SMTPserver-522: 1963484 host connection threshold exceeded for xxx.xxx.xxxxx.xx.xx
> 09-13-2010.00:10:04 SMTPserver-522: 1963485 host connection threshold exceeded for xxx.xxx.xxxxx.xx.xx
> 09-13-2010.00:10:05 SMTPserver-522: 1963486 host connection threshold exceeded for xxx.xxx.xxxxx.xx.xx
>
> the logs on our side look like:
>
> 14 Jun 2010 09:26:08<421 Service not available, closing transmission channel
>
> like 400,000 times a day.
>
> The Listserv logs look normal.  All the list are working fine.