Deployment Guide

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
Dell(config-line-vty)#end
(same applies for radius and line authentication)
VTY MAC-SA Filter Support
The system supports MAC access lists which permit or deny users based on their source MAC address.
With this approach, you can implement a security policy based on the source MAC address.
To apply a MAC ACL on a VTY line, use the same access-class command as IP ACLs.
The following example shows how to deny incoming connections from subnet 10.0.0.0 without displaying a login prompt.
Example of Configuring VTY Authorization Based on MAC ACL for the Line (Per MAC Address)
Dell(conf)#mac access-list standard sourcemac
Dell(config-std-mac)#permit 00:00:5e:00:01:01
Dell(config-std-mac)#deny any
Dell(conf)#
Dell(conf)#line vty 0 9
Dell(config-line-vty)#access-class sourcemac
Dell(config-line-vty)#end
Two Factor Authentication (2FA)
Two factor authentication also known as 2FA, strengthens the login security by providing one time password (OTP) in addition
to username and password. 2FA supports RADIUS authentications with Console, Telnet, and SSHv2.
To perform 2FA, follow these steps:
● When the Network access server (NAS) prompts for the username and password, provide the inputs.
● If the credentials are valid:
○ RADIUS server sends a request to the SMS–OTP daemon to generate an OTP for the user.
○ A challenge authentication is sent from the RADIUS server as Reply–Message attribute.
○ If the Reply–Message attribute is not sent from the RADIUS server, the default text is the Response.
○ 2FA is successful only on providing the correct OTP.
● If the credentials are invalid, the authentication fails.
NOTE: 2FA does not support RADIUS authentications done with SSHv1, REST, Web UI, and OMI.
872 Security