Users Guide

Example of Client-Based SSH Authentication
Dell#ssh 10.16.127.201 ?
-c Encryption cipher to use (for v2 clients only)
-l User name option
-m HMAC algorithm to use (for v2 clients only)
-p SSH server port option (default 22)
-v SSH protocol version
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 64. VTY Access
Authentication Method VTY access-class support? Username access-class
support?
Remote authorization
support?
Line YES NO NO
Local NO YES NO
TACACS+ YES NO YES (with Dell Networking OS
version 5.2.1.0 and later)
RADIUS YES NO YES (with Dell Networking OS
version 6.1.1.0 and later)
Dell Networking OS provides several ways to configure access classes for VTY lines, including:
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