Cannot telnet to RHEL5.4 as a normal user, why ?

Solution Verified - Updated -


  • Red Hat Enterprise Linux 5.4 [telnet server]

  • Microsoft Windows [telnet client]


  • Cannot use telnet to connect to Red Hat Enterprise Linux 5.4 box as a normal user, why ?

  • A normal user cannot telnet to a Red Hat Enterprise Linux 5.4 server from a remote windows system. Has enabled root to login using telnet remotely.  The sessions hangs after the user name and password are typed and times out after 60 seconds.  If the password is typed-in wrong, a "login incorrect" message comes back.


a) Two extra rules were added in /etc/pam.d/system-auth as shown below :

auth        sufficient use_first_pass

was added as the fourth line in the first block of rules.

account     [default=bad success=ok user_unknown=ignore]

was added as the third line in the second block of rules.

Remove them and confirm with a normal system-auth file.

b) Changes in /etc/nsswitch.conf.

The problematic /etc/nsswitch.conf was :

passwd:     files ldap
shadow:     files ldap
group:      files ldap

The above content was changed to:

passwd:     files
shadow:     files
group:      files

Root Cause

Changes in /etc/pam.d/system-auth and /etc/nsswitch.conf

Diagnostic Steps

a) Checked if the user home existed or not.

b) Saw changes in /etc/pam.d/remote and /etc/pam.d/system-auth from the output of 'rpm -Va' in sosreport.

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