Red Hat Bugzilla – Bug 31374
sendmail not closing connections
Last modified: 2007-04-18 12:32:07 EDT
From Bugzilla Helper: User-Agent: Mozilla/4.76 [en] (X11; U; Linux 2.4.0-0.99.11smp i686) Sendmail appears to be not closing connections when a novell groupwise or microsoft server attaches to it. It appears that those servers are unable to deliever the mail to sendmail and sendmail never closes the connection with them. When a ps aux is performed there are many sendmail processes open after some time, and mail from these hosts is not flowing. *nix based hosts do not have any problem delivering mail. Reproducible: Always Steps to Reproduce: 1.Setup the mail server to receive mail. 2.test mail server using other *nix based machines (works properly) 3.send a message from an earthlink dialup account or novell gropwise to the new mail server Actual Results: once earthlinks mail server attempt to connect to sendmail the connection never closes and the sendmail process also never ends. This causes a memmory leak and eventually will crash the machine if left unattended. Expected Results: The mail should be delivered just as it would if it came from a *nix machine. I am running the sendmail that came with redhat 7.1 beta. After a while of being online the machine slows to a crawl as it's memmory is slowly eaten away by sendmail. Another command "lsof -i +M" shows that there are connections still open to the earthlink mail servers.
I recently upgraded sendmail to the newest version (8.11.3), but the problem still persists.
I noticed two things after upgrading a system to Red Hat 7.1: 1. sendmail now uses tcpwrappers by default. If you have an /etc/hosts.deny with ALL:ALL, then you must specifically allow connections to sendmail from hosts you which to allow to connect in /etc/hosts.allow: sendmail: smtp.domain1 smtp.domain2 .... 2. sendmail by default no longer listens on anything other than the loopback interface. If you want it to listen on all interfaces, you need to edit /etc/mail/sendmail.cm, comment out this line with dnl like so: dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA' then rebuild /etc/sendmail.cf with: m4 /usr/share/sendmail-cf/m4/cf.m4 /etc/mail/sendmail.mc > /etc/sendmail.cf then restart sendmail.
I "upgraded" from RedHat 7.0 to 7.1 and still haven't succeeded in getting my workstation to accept incoming e-mail over the network, even after the above change to sendmail.mc. 'telnet localhost 25' on my workstation works, but the system is still refusing connections from anywhere else. /etc/hosts.allow and /etc/hosts.deny on my workstation are both empty (except for comments).
My mistake. I didn't realize that the 'dnl' string was how to comment it out. Is there any good reason why Redhat made seemingly arbitrary changes to the mail configuration on 7.1 (defeating incoming mail, turning off the mbox handling in the imap daemon) without bothering to put a giant Release Note somewhere?
The release notes had some comments about sendmail in them. I hope adding further sendmail docu for the next release is possible. Thanks, Florian La Roche