Login Problems - Novell LINUX ENTERPRISE SERVER 10 SP2 - INSTALLATION AND ADMINISTRATION Installation Manual

51.4 Login Problems

Login problems are those where your machine does, in fact, boot to the expected wel-
come screen or login prompt, but refuses to accept the username and password or accepts
them but then does not behave properly (fails to start the graphic desktop, produces
errors, drops to a command line, etc.).
51.4.1 Valid Username and Password
Combinations Fail
This usually occurs when the system is configured to use network authentication or
directory services and, for some reason, is unable to retrieve results from its configured
servers. The root user, as the only local user, is the only user that can still log in to
these machines. The following are some common reasons why a machine might appear
functional but be unable to process logins correctly:
• The network is not working. For further directions on this, turn to Section 51.5,
"Network Problems" (page 933).
• 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 Section 51.5, "Network
Problems" (page 933).
• 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 Chapter 27, Authentication with PAM (page 497).
Common Problems and Their Solutions 927