Here are some common things to check when no mail is going out from your lists.

====== I'm going to assume Sendmail as the MTA (its still the most commonly found - though postfix is gaining ground):

0. Check_perms. In all cases you should start by checking the permissions on the files that were setup:

   ~mailman/bin/check_perms

1. Cron. Make sure that the cron daemon is running

   ps -aux |grep cron |grep -v grep

   This will print out the process information about the cron daemon. If it returns a blank line, then cron is NOT running.

2. Aliases. To create a mailman list you ran "newlist" and it printed out four lines that you needed to copy to the /etc/aliases file (or wherever your MTA goes to find its aliases). Check that the aliases are in /etc/aliases:

   grep wrapper /etc/aliases

   Even if the aliases are there, you may still need to reset the aliases hash table so that it includes this new alias information:

   newaliases

   Here is a typical alias listing for a group called "sys":

   ## system mailing list sys: "|/home/mailman/mail/wrapper post sys" sys-admin: "|/home/mailman/mail/wrapper mailowner sys" sys-request: "|/home/mailman/mail/wrapper mailcmd sys" sys-owner: sys-admin

3. Smrsh. Check to see if your MTA uses smrsh. Red Hat as well as a few other distributions automatically setup Sendmail to use smrsh. Smrsh stops Sendmail from running a script or other program that is included in an alias. Mailman uses a program called "wrapper" to run all of its aliases (see the alias examples above):

   grep "smrsh" sendmal.cf

   If this comes up blank then Sendmail does not use smrsh; if not, then your server is probably running smrsh and you need to make sure that smrsh is setup to allow Mailman's wrapper program to run. Locate the smrsh directory and do an ls -l of that directory. On Red Hat:

   ls -l /etc/smrsh

   and the output should be similar to:

   wrapper -> /home/mailman/mail/wrapper

4. Interface. Some distributions in a noble "attempt" to limit the number of open relays on the internet, default Sendmail so that it listens to a limited number of interfaces. The default interface that Mailman list's use is localhost (127.0.0.1) - this is configurable in Mailman's mm_cfg.py file. To check Sendmail's configuration file:

   grep "Port" sendmail.cf

   This will list out the DeamonPortOption and indicate the interfaces it listens on (0.0.0.0 would mean all interfaces).

   You can also check out which interfaces your MTA is listening on by using:

   netstat -na |grep ":25 "

5. Qrunner. If you are running Mailman 3.0x then qrunner is run every minute via a cron job (that is why cron *must* be running for Mailman to work). Try running the program by hand. The exact syntax can be found in Mailman's cron jobs:

   su mailman crontab -l

   Here is an example of running qrunner by hand:

   su mailman /usr/bin/python -S /home/mailman/cron/qrunner

   If this generates any errors then send those to the list for diagnosis - or look at the last few lines of errors and search the list for key words from the error messages.

6. Locks. A errant lock file can stop a list from processing as Mailman waits for the lock to be removed. Since your list is not sending, we shall assume that no lock files should be on the list and that it is safe to delete any we find.

   ls -l ~mailman/locks

   The output will be something like:

   qrunner.lock.moya.trilug.org.22845

   This indicates that process # 22845 created the lock. To look at this process and see what it is (if it still exists):

   ps aux |grep 22845 |grep -v grep

7. Logs. If you don't have any of the common problems above, then you should look for errors in your log files.

   First look for errors in your MTA log files. On Red Hat that would be in /var/log/maillog.

   Look in the log starting at the time you sent a test message. You should see your initial message come in and be passed onto to your Mailman list, afterwards you may see warnings or errors caused by Mailman trying to send out mail to the members of the list.

   Next look in Mailman's logs. The files are in ~mailman/logs/. There are several logs to look in for problems: error smtp-failure smtp vette config post

   Note: if you look in the qrunner log you will see several warnings about "Could not acquire qrunner lock", these are actually normal and are NOT a problem.

   Every line in the log files is dated so you should be able to isolate the place in the log files to start looking, based on when your problem started.

8. Qfiles. You may have a malformed email (or one that is simply too big) clogging up the flow of mail to your lists. Mail that is queued up by Mailman is stored in the directory: ~mailman/qfiles

   Move any files out of the directory and into a temporary directory, then send a new test message to your list. If that works, then you can move some of the old queued up files back and let those process. If it stops working again then you have a bad message in that batch - delete them or copy them to a different temporary directory.

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Please feel free to critic and expand on this. I'm hoping that it proves useful as a starting point for folks having mail-flow problems.

-- Jon Carnes