If the IP address in the RSA key does not match the IP address from which you attempt to log in, the following message appears. Inthis case, verify that the name and IP address of the client is contained in the file /etc/hosts: RSA Authentication Error.TelnetTo use Telnet with SSH, first enable SSH, as previously described.By default, the Telnet daemon is enabled. If you want to disable the Telnet daemon, use the following command, or disable Telnet inthe startup config. To enable or disable the Telnet daemon, use the [no] ip telnet server enable command.Example of Using Telnet for Remote LoginDell(conf)#ip telnet server enableDell(conf)#no ip telnet server enableVTY Line and Access-Class ConfigurationVarious methods are available to restrict VTY access in Dell Networking OS. These depend on which authentication scheme you use— line, local, or remote.Table 48. VTY AccessAuthentication Method VTY access-class support? Username access-classsupport? Remote authorizationsupport?Line YES NO NOLocal NO YES NOTACACS+ YES NO YES (with Dell Networking OSversion 5.2.1.0 and later)RADIUS YES NO YES (with Dell Networking OSversion 6.1.1.0 and later)Dell Networking OS provides several ways to configure access classes for VTY lines, including:• VTY Line Local Authentication and Authorization• VTY Line Remote Authentication and AuthorizationVTY Line Local Authentication and AuthorizationDell Networking OS 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.Dell Networking OS can assign different access classes to different users by username. Until users attempt to log in, Dell NetworkingOS does not know if they will be assigned a VTY line. This means that incoming users always see a login prompt even if you haveexcluded them from the VTY line with a deny-all access class. After users identify themselves, Dell Networking OS retrieves theaccess 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 youconfigure RADIUS authentication.Security 651
