Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007 Installation Manual page 939

• DNS is not working at the moment (which prevents GNOME or KDE from working
and the system from making validated requests to secure servers). One indication
that this is the case is that the machine takes an extremely long time to respond to
any action. Find more information about this topic in
Problems" (page 926).
• If the system is configured to use Kerberos, the system's local time might have
drifted past the accepted variance with the Kerberos server time (this is typically
300 seconds). If NTP (network time protocol) is not working properly or local NTP
servers are not working, Kerberos authentication ceases to function because it de-
pends on common clock synchronization across the network.
• The system's authentication configuration is misconfigured. Check the PAM confi-
guration files involved for any typographical errors or misordering of directives.
For additional background information about PAM and the syntax of the configu-
ration files involved, refer to
In all cases that do not involve external network problems, the solution is to reboot the
system into single-user mode and repair the configuration before booting again into
operating mode and attempting to log in again. To boot into single-user mode:
1 Reboot the system. The boot screen appears, offering a prompt.
2 Enter 1 at the boot prompt to make the system boot into single-user mode.
3 Enter the username and password for root.
4 Make all the necessary changes.
5 Boot into the full multiuser and network mode by entering telinit 5 at the
command line.
51.4.2 Valid Username and Password Not
Accepted
This is by far the most common problem users encounter, because there are many reasons
this can occur. Depending on whether you use local user management and authentication
or network authentication, login failures occur for different reasons.
Chapter 27, Authentication with PAM
Common Problems and Their Solutions
Section 51.5, "Network
(page 495).
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