Dell S4048T, Configuration Manual

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Dell Networking OS can assign different access classes to different users by username. Until users attempt to
log in, Dell Networking OS 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, Dell Networking OS retrieves the access class from the local database and
applies it. (Dell Networking OS then can 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.
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
Dell Networking OS 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. Dell Networking
OS does not need to know the identity of the incoming user and can immediately apply the access class. If
the authentication method is RADIUS, , or line, and you have configured an access class for the VTY
line, Dell Networking OS immediately applies it. If the access-class is set to deny all or deny for the incoming
subnet, Dell Networking OS 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 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
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
Dell(config-line-vty)#end
(same applies for radius and line authentication)
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