Troubleshooting Ssh; Telnet; Vty Line And Access-Class Configuration - Dell S3048-ON Configuration Manual

Example of Client-Based SSH Authentication
Dell#ssh 10.16.127.201 ?
-c
-l
-m
-p
-v

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 65. VTY Access
Authentication Method
Line
Local
TACACS+
RADIUS
Dell Networking OS provides several ways to configure access classes for VTY lines, including:
• VTY Line Local Authentication and Authorization
Encryption cipher to use (for v2 clients only)
User name option
HMAC algorithm to use (for v2 clients only)
SSH server port option (default 22)
SSH protocol version
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)
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