Today I was working on a server running SLES10 with LDAP authentication enabled. I tried to add a local user account with home directory /dev/null, but useradd complained that this was an invalid directory. So I manually edited /etc/passwd and changed the home directory.

While editing the passwd file, I found the following line at the end: +:::::: Since this line looked rather strange to me, I removed the line from the passwd file. Guess what happened... LDAP authentication no longer worked. So, should you ever find this line in your passwd file, just leave it there ;-)