User Authentication 3

Configuring the Secure Shell

The Berkley-standard includes remote access tools originally designed for Unix systems. Some of these tools have also been implemented for Microsoft Windows and other environments. These tools, including commands such as rlogin (remote login), rsh (remote shell), and rcp (remote copy), are not secure from hostile attacks.

The Secure Shell (SSH) includes server/client applications intended as a secure replacement for the older Berkley remote access tools. SSH can also provide remote management access to this switch as a secure replacement for Telnet. When the client contacts the switch via the SSH protocol, the switch generates a public-key that the client uses along with a local user name and password for access authentication. SSH also encrypts all data transfers passing between the switch and SSH-enabled management station clients, and ensures that data traveling over the network arrives unaltered.

Note that you need to install an SSH client on the management station to access the switch for management via the SSH protocol.

Note: The switch supports both SSH Version 1.5 and 2.0 clients.

Command Usage

The SSH server on this switch supports both password and public key authentication. If password authentication is specified by the SSH client, then the password can be authenticated either locally or via a RADIUS or TACACS+ remote authentication server, as specified on the Authentication Settings page

(page 3-52). If public key authentication is specified by the client, then you must configure authentication keys on both the client and the switch as described in the following section. Note that regardless of whether you use public key or password authentication, you still have to generate authentication keys on the switch (SSH Host Key Settings) and enable the SSH server (Authentication Settings).

To use the SSH server, complete these steps:

1.Generate a Host Key Pair – On the SSH Host Key Settings page, create a host public/private key pair.

2.Provide Host Public Key to Clients – Many SSH client programs automatically import the host public key during the initial connection setup with the switch. Otherwise, you need to manually create a known hosts file on the management station and place the host public key in it. An entry for a public key in the known hosts file would appear similar to the following example:

10.1.0.54 1024 35 15684995401867669259333946775054617325313674890836547254 15020245593199868544358361651999923329781766065830956 10825913212890233 76546801726272571413428762941301196195566782 59566410486957427888146206 519417467729848654686157177393901647793559423035774130980227370877945452 4083971752646358058176716709574804776117

3.Import Client’s Public Key to the Switch – Use the copy tftp public-key command (page 4-63)to copy a file containing the public key for all the SSH client’s granted management access to the switch. (Note that these clients must

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