Hi folks,
I'm wondering if anyone has suggestions for how I can diagnose a rare
problem with my mail server. I have a feeling that it has something
to do with the many-layered authentication system of Mac OS X Server,
so any help would be appreciated.
I seem to have email problems with only one other site. Their site
times out after one minute of waiting for a response to an SMTP
connection, and considers the destination to be invalid at that
point. However, my site doesn't show the Sendmail ESMTP response
until about 60 seconds after the initial connection. I'd like to cut
down that response time, but I'm not sure exactly where to look.
First of all, I have a Xserve dual G5 node running Mac OS X Server
10.4.11 with a fairly basic setup, plus Sendmail 8.13.8 that I
compiled and installed myself. It's been running since 2006, only
rebooted once, and tens of thousands of emails have successfully
passed through. It's only recently that I called a client on the
phone to find out why they had not responded to my email, and that's
when I learned it had been bounced by their system.
Other than telling their IT staff to change a policy, it seems that
there must be some things I can try. But I don't really know where to
start diagnosing this problem. As I mentioned, my suspicion is that
the Mac OS X Server authentication stack is causing the delay. In
particular, I suspect that I have some sort of compatibility protocol
enabled which is not really used or even needed, but the timeout is
possibly forced because I don't know how to disable the unused
protocol. Assuming my suspicion is correct, how exactly does one
streamline the authentication process on Mac OS X Server Tiger?
Alternatively, if anyone knows sendmail and has an idea of how to
diagnose the source of this delay, please help. I should point out
that I suffered a DOS attach right around the time when I was first
configuring this server - resulting in about 2,000 forked sendmail
processes waiting on incoming but fraudulent email connections - and
my fix was to set the sendmail option which limits incoming
connections to one per second. I'm a little suspicious that it may
have become a one per minute limit, but I somehow doubt that. In
addition to the one SMTP connect per second, I also have reverse DNS
lookups and ip blacklisting active. Those surely add some delay, but
the fact that it always takes a minimum of 60 seconds seems more like
a timeout than a DNS lookup delay.
Thanks for any clues or pointers,
Brian
P.S. Please don't suggest that I switch back to postfix. I left it
for a reason. I prefer sendmail. At any rate, I'm certain that
sendmail is not limited to a 60-second response time, or else my
client would not be able to send to many sites on the internet. There
must be a solution which can speed up my mail server. Also, I'm not
keen on updating to Leopard, because this is a PowerPC Xserve, and I'm
not convinced that Leopard was ever intended to run well on PPC (if
you have references to the contrary, send those offlist). You may be
getting the (correct) impression that I'm a little out of touch with
the IT community! :-)
_______________________________________________
MacOSX-admin mailing list
[email protected]
http://www.omnigroup.com/mailman/listinfo/macosx-admin
