Mailer Daemon: User Unknown

Support knowledgebase (passwd)

Symptom:

When sending e-mails to a user, you receive the mailer-daemon message user unknown. This happens eventhough everything seems to be correctly configured and the user is included in /stc/passwd.

Cause:

The user name contains one or more upper case letters. The upper case will be first converted into lower case (lower/upper case writing must be the same in e-mails). Then it will be checked whether the user is included in /etc/passwd or not.

Solution:

There has been a long discussion on this problem being a bug or not. However, we will not invest too much time in repairing it because it is extremely unusual (only one person has reported it so far).

Write the login name in lower case!

Stephan Hegering (sh@leverkusen.netsurf.de) writes about it:

You must edit /etc/sendmail.cf ;-) Insert a "u" at the flags (F=...) at the appropriate mailer in this mailer specification. Hint: Look for electric after "Mlocal,".
F=u --> Preserve uppercase for username
Otherwise, the user name in the address will be converted into lower case.

This tip is not mine, but Dieter Brueggemann's (Bert@stud-mailer.uni-marburg.de)

Note: After doing this, set SENDMAIL_TYPE=no in the file /etc/rc.config. In this way, /etc/sendmail.cf will not be overwritten.


Keywords: MAILER, USER UNKNOWN, PASSWD, SENDMAIL

Feedback welcome: Send Mail to kfr@suse.de (Please give the following subject: SDB-passwd)
SDB-passwd, Copyright SuSE Linux AG, Nürnberg, Germany - Version: 03. Feb 1996
SuSE Linux AG - Last generated: 14. Jan 2002 by kfr (sdb_gen 1.40.0)