On a server I have exim 3.12 running on port 25 and 26.
Now, the problem is that while port 26 answers quickly, port 25
doesn't. It simply hangs there. Exim has not reached the max-limits on
number of connections, and I have tried increasing
smtp_connect_backlog too. After a lengthy period (20-30 seconds) it
responds.
Now, this is a heavy loaded server, but I find it strange that the
instance on port 26 is so much quicker.
There are no DNS/ident problems. Both instances of exim run with the
same config-file.
What does exim do before kicking another exim into action? Any ideas?
Has anybody compared the throughput of queue_only with dedicated
queue-runners in comparison with the normal deliver at once?
