Troubleshooting Ssh; Telnet; Vty Line And Access-Class Configuration - Dell S4820T Configuration Manual

Troubleshooting SSH

To troubleshoot SSH, use the following information.
You may not bind id_rsa.pub to RSA authentication while logged in via the console. In this case, this
message displays:%Error: No username set for this term.
Enable host-based authentication on the server (Dell Networking system) and the client (Unix machine).
The following message appears if you attempt to log in via SSH and host-based is disabled on the client.
In this case, verify that host-based authentication is set to "Yes" in the file ssh_config (root permission is
required to edit this file): permission denied (host based).
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. In this case, verify that the name and IP address of the client is contained in
the file /etc/hosts: RSA Authentication Error.

Telnet

To 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 in the startup config. To enable or disable the Telnet daemon, use the [no]
ip telnet server enable command.
The Telnet server or client is VRF-aware. You can enable a Telnet server or client to listen to a specific
VRF by using the vrf vrf-instance-name parameter in the telnet command. This capability
enables a Telent server or client to look up the correct routing table and establish a connection.
Example of Using Telnet for Remote Login
Dell(conf)#ip telnet server enable
Dell(conf)#no ip telnet server enable

VTY Line and Access-Class Configuration

Various methods are available to restrict VTY access in Dell Networking OS. These depend on which
authentication scheme you use — line, local, or remote.
Table 69. VTY Access
Authentication Method
Line
Local
TACACS+
RADIUS
Dell Networking OS provides several ways to configure access classes for VTY lines, including:
842
VTY access-class
support?
YES
NO
YES
YES
Username access-class
support?
NO
YES
NO
NO
Remote authorization
support?
NO
NO
YES (with Dell
Networking OS version
5.2.1.0 and later)
YES (with Dell
Networking OS version
6.1.1.0 and later)
Security