Configuring Secure Shell (SSH)

 

Configuring the Switch for SSH Operation

 

 

Notes

When you generate a host key pair on the switch, the switch places the key

 

pair in flash memory (and not in the running-config file). Also, the switch

 

maintains the key pair across reboots, including power cycles. You should

 

consider this key pair to be "permanent"; that is, avoid re-generating the key

 

pair without a compelling reason. Otherwise, you will have to re-introduce the

 

switch’s public key on all management stations you have set up for SSH access

 

to the switch using the earlier pair.

 

Removing (zeroing) the switch’s public/private key pair renders the switch

 

unable to engage in SSH operation and automatically disables IP SSH on the

 

switch. (To verify whether SSH is enabled, execute show ip ssh.) However, any

 

active SSH sessions will continue to run, unless explicitly terminated with the

 

CLI kill command.

 

To Generate or Erase the Switch’s Public/Private RSA Host Key Pair.

 

 

Because the host key pair is stored in flash instead of the running-config file,

 

it is not necessary to use write memory to save the key pair. Erasing the key

 

pair automatically disables SSH.

 

Syntax: crypto key generate ssh [rsa]

 

Generates a public/private key pair for the switch. If a

 

switch key pair already exists, replaces it with a new

 

key pair. (See the Note, above.)

 

crypto key zeroize ssh [rsa]

 

Erases the switch’s public/private key pair and dis-

 

ables SSH operation.

 

show crypto host-public-key

 

Displays switch’s public key. Displays the version 1

 

and version 2 views of the key.

 

[ babble ]

 

Displays hashes of the switch’s public key in

 

phonetic format. (See “Displaying the Public

 

Key” on page 6-14.)

 

[ fingerprint ]

 

Displays fingerprints of the switch’s public key

 

in hexadecimal format. (See “Displaying the

 

Public Key” on page 6-14.)

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