Installing and Administering Internet Services

Chapter 4 153
Installing and Administering sendmail
Troubleshooting sendmail
Verifying Address Resolution and Aliasing
In order to deliver a message, sendmail must first resolve the recipient
addresses appropriately. To determine how sendmail would route mail
to a particular address, issue the following command:
/usr/sbin/sendmail -bv -v -oL10 address [address...]
The -bv (verify mode) option causes sendmail to verify addresses
without collecting or sending a message.
The -v (verbose) flag causes sendmail to report alias expansion and
duplicate suppression.
The -oL10 (log level) option sets the log level to 10. At log level 10 and
above, sendmail -bv reports the mailer and host to which it resolves
recipient addresses.
For hosts that resolve to IPC mailers, MX hosts are not reported when
using verify mode, because MX records are not collected until delivery is
actually attempted.
If the address is not being resolved as you expect, you may have to
modify one or more of the following:
• The sendmail configuration file.
• The files or programs from which file classes are generated.
• The name server configuration.
• The UUCP configuration.
More detailed information about how the configuration file is rewriting
the recipient addresses is provided by address test mode:
/usr/sbin/sendmail -bt
Verifying Message Delivery
You can observe sendmail’s interaction with the delivery agents by
delivering the message in verbose mode, as in the following example:
/usr/sbin/sendmail -v [e-mail]
sendmail responds with the following information:
[e-mail]... aliased to [e-mail]
sendmail is now ready for you to type a message. After the message,
type a period (.) on a line by itself, as in the following example: