sendmail sluggish when opening connection

[Brian Willoughby]

Hi folks,

I set up sendmail in place of postfix on my Tiger Xserve, and haven't  
touched it since 2007.  I've been receiving tons of email and run a  
few mailing lists.

However, I finally ran into someone who cannot send to me because  
their IT department has a 60-second timeout when sending via SMTP,  
and my sendmail daemon takes that much time to respond to a simple  
telnet connection.

I'm not really sure when this started acting up, but I'm sure that it  
did not always take this long.  Recently, I've had to shut down ssh  
access from unlisted ip addresses, due to attacks targeting my server  
(along with many others, I'm sure), but I think this is probably  
unrelated, since sendmail is not using ssh (yet) on my setup.

I've also got a few options selected in sendmail to throttle incoming  
connections, by limiting new connections to one per second.  That  
should not be causing a delay of 60 seconds, though, unless the  
parameter has the wrong units.  There are probably a few other  
throttling options enabled, since the week before I installed this  
Xserve in 2006 I suffered a DoS attack attempting to scan SMTP for  
mailboxes.

I tried editing /etc/mail/sendmail.cf to remove obvious things like  
TrustAuthMech KERBEROS_V5 and AuthMechanisms GSSAPI KERBEROS_V5,  
since I'm pretty sure I don't have those set up for sendmail anyway.  
But I still get the long timeout.

Does anyone have any suggestions as you how I could diagnose this?  I  
assume I could run sendmail in gdb, since I did compile in on that  
machine, but that doesn't seem like the smartest first step.

P.S. Please don't tell me to switch to postfix, that's not going to  
be received as a helpful response.  I've been using sendmail since  
the early nineties, and postfix is a bit of a step in the wrong  
direction for me.

Brian Willoughby
Sound Consulting

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[LuKreme]

On Jun 23, 2009, at 6:44, Brian Willoughby <brianw@...> wrote:
> who cannot send to me because their IT department has a 60-second  
> timeout when sending via SMTP, and my sendmail daemon takes that  
> much time to respond to a simple telnet connection

Their server is badly configured and a LOT of servers will be unable  
to get mail from them. The recommended setting is 10 minutes, as I  
recall. Send them a copy of RFC 822 or 2822, whichever is appropriate.

--
Sent from my Bluetooth enabled iTouch.

>
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