API Guide

The system provides several ways to configure access classes for VTY lines, including:
• VTY Line Local Authentication and Authorization
• VTY Line Remote Authentication and Authorization
VTY Line Local Authentication and Authorization
The system retrieves the access class from the local database.
To use this feature:
1. Create a username.
2. Enter a password.
3. Assign an access class.
4. Enter a privilege level.
You can assign line authentication on a per-VTY basis; it is a simple password authentication, using an access-class as authorization.
Configure local authentication globally and configure access classes on a per-user basis.
The system can assign different access classes to different users by username. Until users attempt to log in, the system does not know if
they will be assigned a VTY line. This means that incoming users always see a login prompt even if you have excluded them from the VTY
line with a deny-all access class. After users identify themselves, the system retrieves the access class from the local database and applies
it. (The system can then close the connection if a user is denied access.)
NOTE: If a VTY user logs in with RADIUS authentication, the privilege level is applied from the RADIUS server only if you
configure RADIUS authentication.
The following example shows how to allow or deny a Telnet connection to a user. Users see a login prompt even if they cannot log in. No
access class is configured for the VTY line. It defaults from the local database.
NOTE:
For more information, refer to Access Control Lists (ACLs).
Example of Configuring VTY Authorization Based on Access Class Retrieved from a Local Database (Per User)
Dell(conf)#user gooduser password abc privilege 10 access-class permitall
Dell(conf)#user baduser password abc privilege 10 access-class denyall
Dell(conf)#
Dell(conf)#aaa authentication login localmethod local
Dell(conf)#
Dell(conf)#line vty 0 9
Dell(config-line-vty)#login authentication localmethod
Dell(config-line-vty)#end
VTY Line Remote Authentication and Authorization
The system retrieves the access class from the VTY line.
The Dell Networking OS takes the access class from the VTY line and applies it to ALL users. The system does not need to know the
identity of the incoming user and can immediately apply the access class. If the authentication method is RADIUS, TACACS+, or line, and
you have configured an access class for the VTY line, the system immediately applies it. If the access-class is set to deny all or deny for
the incoming subnet, the system closes the connection without displaying the login prompt. The following example shows how to deny
incoming connections from subnet 10.0.0.0 without displaying a login prompt. The example uses TACACS+ as the authentication
mechanism.
Example of Configuring VTY Authorization Based on Access Class Retrieved from the Line (Per Network Address)
Dell(conf)#ip access-list standard deny10
Dell(conf-ext-nacl)#permit 10.0.0.0/8
Dell(conf-ext-nacl)#deny any
Dell(conf)#
Dell(conf)#aaa authentication login tacacsmethod tacacs+
Dell(conf)#tacacs-server host 256.1.1.2 key Force10
Dell(conf)#
Dell(conf)#line vty 0 9
Dell(config-line-vty)#login authentication tacacsmethod
Dell(config-line-vty)#
Dell(config-line-vty)#access-class deny10
Security
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