Configuring Secure Shell (SSH)

Configuring the Switch for SSH Operation

With steps 1 - 3, above, completed and SSH properly configured on the switch, if an SSH client contacts the switch, login authentication automatically occurs first, using the switch and client public-keys. After the client gains login access, the switch controls client access to the manager level by requiring the passwords configured earlier by the aaa authentication ssh enable command.

Syntax: copy tftp pub-key-file < ip-address> < filename >

 

Copies a public key file into the switch.

 

aaa authentication ssh login public-key

 

Configures the switch to authenticate a client public-key at

 

the login level with an optional secondary password method

 

(Default: none).

 

 

Caution

To allow SSH access only to clients having the correct public key, you must

 

configure the secondary (password) method for login public-keyto none.

 

Otherwise a client without the correct public key can still gain entry by

 

submitting a correct local login password.

 

Syntax: aaa authentication ssh enable < local tacacs radius > < local none >

 

 

Configures a password method for the primary and second-

 

ary enable (Manager) access. If you do not specify an

 

optional secondary method, it defaults to none. If the primary

 

password method is local, you cannot use local for the sec-

 

ondary password method.

 

For example, assume that you have a client public-key file named Client-

 

Keys.pub (on a TFTP server at 10.33.18.117) ready for downloading to the

 

switch. For SSH access to the switch you want to allow only clients having a

 

private key that matches a public key found in Client-Keys.pub.For Manager-

 

level (enable) access for successful SSH clients you want to use TACACS+ for

 

primary password authentication and local for secondary password authenti-

 

cation, with a Manager username of "1eader" and a password of "m0ns00n".

 

To set up this operation you would configure the switch in a manner similar

 

to the following:

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