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Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
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Chapter 30 Configuring Switch Access Using AAA
Configuring Authentication
Kerberos Clients NOT Mandatory
Kerberos Credentials Forwarding Enabled
Kerberos Pre Authentication Method set to None
Kerberos config key:
Kerberos SRVTAB Entries
Srvtab Entry 1:host/[email protected] 0 932423923 1 1 8 03;;5>00>50;0=0=0
Srvtab Entry 2:host/[email protected] 0 933974942 1 1 8 00?58:127:223=:;9
Console> (enable)
Deleting an SRVTAB Entry
To delete an SRVTAB entry, perform this task in privileged mode:
This example shows how to delete an SRVTAB entry:
Console> (enable) clear kerberos srvtab entry host/[email protected] 0
Console> (enable)
Enabling Credentials Forwarding
A user authenticated to a Kerberized switch has a TGT and can use it to authenticate to a host on the
network. However, if forwarding is not enabled and a user tries to list credentials after authenticating to
a host, the output will show that no Kerberos credentials are present.
To enable credentials forwarding, configure the switch to forward user TGTs when they authenticate
from the switch to Kerberized remote hosts on the network using Kerberized Telnet.
As an additional layer of security, you can configure the switch so that after users authenticate to it, these
users can authenticate only to other services on the network with Kerberized clients. If you do not make
Kerberos authentication mandatory and Kerberos authentication fails, the application attempts to
authenticate users using the default method of authentication for that network service. For example,
Telnet prompts for a password.
To configure clients to forward user credentials as they connect to other hosts in the Kerberos realm,
perform this task in privileged mode:
This example shows how to configure clients to forward user credentials and verify the configuration:
Console> (enable) set kerberos credentials forward
Kerberos credentials forwarding enabled
Console> (enable) show kerberos
Kerberos Local Realm:CISCO.COM
Kerberos server entries:
Realm:CISCO.COM, Server:187.0.2.1, Port:750
Task
Command
Delete the SRVTAB entry for a particular
Kerberos principal.
clear kerberos srvtab entry kerberos-principal
principal-type
Task
Command
Step 1
Enable all clients to forward user credentials upon
successful Kerberos authentication.
set kerberos credentials forward
Step 2
(Optional) Configure Telnet to fail if clients cannot
authenticate to the remote server.
set kerberos clients mandatory