Unix Tipz & Tricz

In some cases we face the issues while doing switch user (su) the error messages as “user unknown” will occur on the server even though the user is present in the /etc/passwd and /etc/shadow files.

This is due to the lack of setuid permissions on the file /usr/bin/su.

 Check the permissions and enable the SETUID for the command /usr/bin/su

#ls -l  /usr/bin/su

-r-sr-xr-x   1 root     sys        25748 May 25  2005 /usr/bin/su

After enabling the SETUID on the server switch user(su) will work fine.