6-11
Configuring Secure Shell (SSH)
Configuring the Switch for SSH Operation
N o t e s
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.)
