Large number connections in CLOSE_WAIT state

Hi,

Over the past weekend I noticed a problem with CLOSE_WAIT connections.
This problem has had a serious mail flow disruption effect and I hope
someone can give me some idea as to what can be done about it.

It appears that SMTP connections from one particular host always fails.
There never appears any connection information in any of the log files.

The site [206.79.27.5] does not have any DNS entries and appears to be
poorly connected. Telnet/finger attempts (in order to find out what it is)
all timeout.

The problem is that the CLOSE_WAIT connections cause the controlling Exim
to stay active indefinitely. This in turn causes the concurrency limit to
be exceeded. Killing all "frozen" Exim processes seems to be the only
solution. However, doing this every +/- 10 hours is not exactly ideal...

If no in-system solution is possible, I guess blocking the connection at
our firewall is the only other alternative...

Comments?

Thanks,
Hans
--
Hans Grobler,
grobh@???,
Stellenbosch University, South Africa