I haven't made any changes to my server for months, but this morning sendmail stopped relaying with SMTP from authorized users. Their mail clients just block until they timeout, but incoming mail is still accepted. I've tried restarting sendmail and rebooting the server, to no avail. Squirrelmail works and all other services are running.

There are a lot of entries in maillog like this:

[ddd.ddd.ddd.ddd] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA

I submitted a trouble ticket on this an hour ago, but have had no response yet. Can anyone suggest how I might resolve this issue?

Thanks!

JUST AN FYI:

If you are currently experiencing slow smtp connections on sendmail, enough to cause timeouts, (ie. telnet to port 25 and wait 30 seconds or more to see the welcome banner,) it could be your dnsbl entry.

If you have a line like this in your sendmail.mc...



comment it out, do the "m4 dance" and restart sendmail. It worked for me.

Thanks for the suggestion. Do you happen to know which of the sendmail.mc files is the one to dance with on an Ensim system?

/etc/mail/sendmail.mc
/usr/lib/opcenter/sendmail/install/sendmail.mc
/home/virtual/FILESYSTEMTEMPLATE/siteinfo/etc/mail/sendmail.mc
/home/virtual/site2/fst/etc/mail/sendmail.mc

/usr/lib/opcenter/sendmail/install/sendmail.mc is the one you want, then.

m4 /usr/lib/opcenter/sendmail/install/sendmail.mc > /etc/mail/sendmail.cf

BUT, if you haven't added the dnsbl entry it in the past, it probably won't be in there. Ensim doesn't include it by default.

Thanks for the info, but I haven't referenced ordb.org in the mc file. I did have it in my MailScanner config file, but removed it last year, when they notified that they were shutting down.

I just tried telneting to port 25 and it took over 100 seconds to respond to the EHLO command, so I think you're on to something. Can you think of anything else I should check?

Thanks

In my case it was a delay before the initial "220" greeting which was sendmail trying to look up IP addresses in a dead block list. I don't know what else to look at speciffically. When I googled the problem I read about similar things being caused by ident (port 113) being firewalled, or reverse DNS lookups failing or taking a long time.

One thread said to look in your resolv.conf to see what DNS servers you have set and then do dig @ -x for a revers DNS lookup and note how log it takes to get an answer.

Good luck

EV1 tech have fixed the problem, and it did turn out to be ordb.org. It looks like they fixed it by manually editing /etc/sendmail.cf, as I cannot find a corresponding sendmail.mc file. I don't know if this is the standard location for that file with Ensim 3.5, but if anybody else hits this problem, that's a good place to look.