[Urgent] sendmail not echoing back during smtp connection
Help! I have a production server where sendmail suddenly stopped answering smtp connections! I have tried killing it and restarting it, but this doesn't change anything. The config didnt change, it just started to do this progressively, from what I can see in the logs with increasing numbers of [xxx.xxx.xxx.xxx] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA If I connect to port 25 the connection is established but nothing is echo'd, like no sendmail greeting, no reply whatsoever to smtp commands. So all MTAs are timing out connecting to my server! But the delivery still works fine, ie if I telnet to port 25 and give a valid mail from, rcpt to, data, etc, without waiting for SMTP answers, the mail is delivered fine in my inbox... How is this possible? I have tried everything, even when it doesn't make sense, like allowing all from all in IPFW, restarting sendmail many times, switching configs... short of rebooting the box of course, which probably wouldn't help anyway. LogLevel to 30 just yields a lot of intertwined : --- Mar 24 18:51:54 charon sm-mta[39105]: h2OHkian039105: Milter: no active filter Mar 24 18:51:54 charon sm-mta[39105]: h2OHkian039105: --- 220 charon.dom.tld ESMTP Sendmail 8.12.6/8.12.6; Mon, 24 Mar 2003 18:51:54 +0100 (CET) Mar 24 18:51:54 charon sm-mta[39105]: h2OHkian039105: --- 421 4.4.1 charon.dom.tld Lost input channel from tomts4.bellnexxia.net [209.226.175.10] Mar 24 18:51:54 charon sm-mta[39105]: h2OHkian039105: lost input channel from tomts4.bellnexxia.net [209.226.175.10] to MTA after startup Mar 24 18:51:54 charon sm-mta[39105]: h2OHkian039105: tomts4.bellnexxia.net [209.226.175.10] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA --- But this --- 220 charon.dom.tld ESMTP Sendmail 8... never actually reaches the client. (*but* from time to time there are successful connections in between!) Any ideas? I think I must be cursed or something... Olivier PS: please make sure you CC to me as my address subcribed to the list isnt getting the mails anymore To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
(SOLVED) Re: [Urgent] sendmail not echoing back during smtp connection
On Mon, Mar 24, 2003 at 06:58:21PM +0100, Olivier Dony wrote: Help! I have a production server where sendmail suddenly stopped answering smtp connections! I have tried killing it and restarting it, but this doesn't change anything. The config didnt change, it just started to do this progressively, from what I can see in the logs with increasing numbers of [xxx.xxx.xxx.xxx] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA If I connect to port 25 the connection is established but nothing is echo'd, like no sendmail greeting, no reply whatsoever to smtp commands. So all MTAs are timing out connecting to my server! But the delivery still works fine, ie if I telnet to port 25 and give a valid mail from, rcpt to, data, etc, without waiting for SMTP answers, the mail is delivered fine in my inbox... Here is the explanation if someone ever gets the same problem: DNSBL's are somehow blocking every connection, so the solution is to remove every DNSBL from sendmail's config and restart it and the problem goes away. (A lot of thanks to the sendmail-questions mailing-list :-) I was using 4 of them : relays.ordb.org, list.dsbl.org, dun.dnsrbl.net and spam.dnsrbl.net. I will try and see which one(s) is(are) causing the problem when the mail traffic calms down a bit. This is probably due to the way DNSBL is implemented that nothing is logged regarding this problem and the client is just left there to timeout, and the timeout is really logged. This is what mislead me, but the progressive increase of the did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA messages in the log should be a red flag for anybody using DNSBLs. Hope this can help someone. Thanks for reading ;) Olivier To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-questions in the body of the message
