Greetings
I have been mostly unable to receive email from the FSF Europe Discussion list, and maybe this is happening to others as well. I get lots of entries like
timeout waiting for input from mail-ffm-p.arcor-ip.de during message collect
on the machine receiving email.
Eventually we get 30 (=MaxDaemonChildren) open sendmail connections, and sendmail stops accepting other connections. This is now happening several times per day. A few days ago, I contacted postmaster@mail.arcor-ip.de about this but received no reply (perhaps because of the same problem :) ).
Following a suggestion in http://www.sendmail.org/faq/section3.html#3.10 I added define(`confTO_IDENT',`0s')dnl to our sendmail.mc and some mail from the list arrived, but I now assume there was some coincidence (either that or the postmaster took some temporary corrective measure), since things are now as before. Anyway, I noticed that our IDENT timeout before was just 30s...
I still believe that there may be some problem on the sending side. This has never happened to us with email from other sources, as far as I know. Could it be some firewall in there, maybe something related to "path MTU discovery" as discussed in http://www.sendmail.org/faq/section3.html#3.10 ?
I found this at Google Groups, in thread http://groups.google.com/groups?hl=en&lr=&safe=off&ic=1&th=1...
From: Tom Simpson (wtsimpson@my-deja.com) Subject: Re: redhat linux 6.x and sendmail8..9.3 Newsgroups: comp.mail.sendmail Date: 2000/02/17
[...]
Also from the router side IF it is a Cisco router Check the Version OF IOS and MAKE sure that there is not any problems with the release that you have. I know from personnal experince that anything below 12.07 has problems that cause NAT issues on the 3600 series at least. After a few days the memory gets eatten up by memory leaks and the ftp services stop functioning through the routers, after setting up NAT, they worked fine when we had public IP's on both sides of the routers. (along with who knows what else). After flashing the 3600's to 12.09 from 12.05 & 12.06 ALOT of the problems went away for now on transfering through the router. So this could be a problem to look at as well. IF you have access to a Server(root access that is) run a TCP dump on the outside when you try to send something out, This might help show you where your problem may be. Also watch the NAT translations at the router, on Cisco the enable command is show ip nat trans . This way you can verify that the router is passing the traffic back and forth. Also check to see IF any access-lists are on the interfaces that MIGHT be setup to timeout connections as well.
Please contact me if you find a possible cause for this problem; maybe others are also affected, not only unable to read list email but also getting their sendmail systems blocked from receiving other messages. It would be best if you email me through another route in order to ensure that your message reaches me...
Meanwhile, I'll have to remove myself (temporarily, I hope) from the FSF Europe Discussion mailing list, and if mail-ffm-p.arcor-ip.de insists on lots of retries I may have to filter SMTP traffic from it to artenumerica.com in order to avoid sendmail blocking.
Best regards and thank you in advance
J Esteves