Configuring and Managing MPE/iX Internet Services (August 2002)

Chapter 10
Sendmail for MPE/iX
Troubleshooting
204
Troubleshooting
• Always check syslog when you have problems with Sendmail!
• If you don’t see any syslog events being logged:
— If you are running third-party spooling software with an embedded syslog daemon, you must use that
embedded daemon instead of Syslog/iX to capture Sendmail logging events.
— Verify that the syslog daemon is running.
— Verify that all files used by the syslog daemon have the correct file ownership and permissions.
— Verify that syslog has been configured to log mail events.
• If syslog or e-mail message headers show strange timestamps, verify that the TZ environment variable is
set correctly, preferably in your system logon UDC.
• If syslog shows DNS lookup failures:
— Run the /SENDMAIL/CURRENT/bin/dnscheck script to verify that DNS is configured properly on your
local machine.
— Check with your firewall administrator to make sure your local machine is allowed to talk to your
DNS server(s) via port 53.
• If syslog shows connection failures for remote mail servers, check with your firewall administrator to
make sure your local machine is allowed to talk to those remote mail servers via port 25. If you are not
allowed to talk directly to remote mail servers, you may need to configure a smart host mail relay in
/etc/mail/sendmail.cf or designate alternate relays for specific domains via the mailertable feature.
• Very long delays when a local user is submitting a new e-mail message are indicative of DNS problems.
Check syslog for any errors, and run the /SENDMAIL/CURRENT/bin/dnscheck DNS configuration
validation script.
• If local users are submitting new messages that aren't being delivered:
— Verify that the mail daemon job is running. If the mail daemon is not running, newly submitted
messages are queued in the /var/spool/clientmqueue directory. The mail daemon will process
these queued messages the next time it is started.
— The mail daemon’s delivery queue is the /var/spool/mqueue directory. Users with proper security
can examine the queue files directly, or run /SENDMAIL/CURRENT/bin/mailq to get a formatted
queue listing.
• If remote users are sending messages to the local machine that aren’t being delivered:
— Check syslog to see if the remote mail server is able to connect to the local machine. If you do not see
any connection attempts:
— Talk to your firewall administrator to determine if remote machines are allowed to send e-mail to
your local machine via port 25.
— Talk to your network administrator to verify that your local machine’s DNS entries should be
visible to the remote mail server.
— Verify that the remote users are using valid user addresses (aliases or uppercase USER.ACCOUNT)
and hostnames for your local machine.
• If you make a Sendmail configuration change but the new configuration doesn’t appear to take effect: