Cisco Systems 3130 User Manual
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Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter 7 Configuring Switch-Based Authentication
Controlling Switch Access with Kerberos
Kerberos Operation
A Kerberos server can be a switch that is configured as a network security server and that can
authenticate remote users by using the Kerberos protocol. Although you can customize Kerberos in a
number of ways, remote users attempting to access network services must pass through three layers of
security before they can access network services.
authenticate remote users by using the Kerberos protocol. Although you can customize Kerberos in a
number of ways, remote users attempting to access network services must pass through three layers of
security before they can access network services.
To authenticate to network services by using a switch as a Kerberos server, remote users must follow
these steps:
these steps:
1.
2.
3.
Authenticating to a Boundary Switch
This section describes the first layer of security through which a remote user must pass. The user must
first authenticate to the boundary switch. This process then occurs:
first authenticate to the boundary switch. This process then occurs:
1.
The user opens an un-Kerberized Telnet connection to the boundary switch.
2.
The switch prompts the user for a username and password.
3.
The switch requests a TGT from the KDC for this user.
KEYTAB
3
A password that a network service shares with the KDC. In Kerberos 5
and later Kerberos versions, the network service authenticates an
encrypted service credential by using the KEYTAB to decrypt it. In
Kerberos versions earlier than Kerberos 5, KEYTAB is referred to as
SRVTAB
and later Kerberos versions, the network service authenticates an
encrypted service credential by using the KEYTAB to decrypt it. In
Kerberos versions earlier than Kerberos 5, KEYTAB is referred to as
SRVTAB
4
.
Principal
Also known as a Kerberos identity, this is who you are or what a service
is according to the Kerberos server.
is according to the Kerberos server.
Note
The Kerberos principal name must be in all lowercase characters.
Service credential
A credential for a network service. When issued from the KDC, this
credential is encrypted with the password shared by the network service
and the KDC. The password is also shared with the user TGT.
credential is encrypted with the password shared by the network service
and the KDC. The password is also shared with the user TGT.
SRVTAB
A password that a network service shares with the KDC. In Kerberos 5
or later Kerberos versions, SRVTAB is referred to as KEYTAB.
or later Kerberos versions, SRVTAB is referred to as KEYTAB.
TGT
Ticket granting ticket that is a credential that the KDC issues to
authenticated users. When users receive a TGT, they can authenticate to
network services within the Kerberos realm represented by the KDC.
authenticated users. When users receive a TGT, they can authenticate to
network services within the Kerberos realm represented by the KDC.
1.
TGT = ticket granting ticket
2.
KDC = key distribution center
3.
KEYTAB = key table
4.
SRVTAB = server table
Table 7-2
Kerberos Terms (continued)
Term
Definition