SMC Networks SMC TigerStack III SMC6824MPE User Manual
Page 311
S
YSTEM
M
ANAGEMENT
C
OMMANDS
4-49
3. Import Client’s Public Key to the Switch – Use the copy tftp public-key
command 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
be configured locally on the switch with the username command as
described on page 4-36.) The clients are subsequently authenticated using
these keys. The current firmware only accepts public key files based on
standard UNIX format as shown in the following example for an RSA
Version 1 key:
1024 35 1341081685609893921040944920155425347631641921872958921143173880
05553616163105177594083868631109291232226828519254374603100937187721199696317813
66277414168985132049117204830339254324101637997592371449011938006090253948408482
71781943722884025331159521348610229029789827213532671316294325328189150453063939
16643 [email protected]
4. Set the Optional Parameters – Set other optional parameters, including
the authentication timeout, the number of retries, and the server key size.
5. Enable SSH Service – Use the ip ssh server command to enable the SSH
server on the switch.
6. Configure Challenge-Response Authentication – When an SSH client
attempts to contact the switch, the SSH server uses the host key pair to
negotiate a session key and encryption method. Only clients that have a
private key corresponding to the public keys stored on the switch can gain
access. The following exchanges take place during this process:
a. The client sends its public key to the switch.
b. The switch compares the client's public key to those stored in
memory.
c. If a match is found, the switch uses the public key to encrypt a random
sequence of bytes, and sends this string to the client.
d. The client uses its private key to decrypt the bytes, and sends the
decrypted bytes back to the switch.
e. The switch compares the decrypted bytes to the original bytes it sent.
If the two sets match, this means that the client's private key
corresponds to an authorized public key, and the client is
authenticated.
Note: To use SSH with only password authentication, the host public key
must still be given to the client, either during initial connection or manually
entered into the known host file. However, you do not need to configure the
client’s keys.