LevelOne GSW-2692 manual User Authentication

User Authentication 3

3.Import Client’s Public Key to the Switch – Use the copy tftp public-keycommand (page 4-65) 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 via the User Accounts page as described on page 3-35.) 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

05553616163105177594083868631109291232226828519254374603100937187721199

69631781366277414168985132049117204830339254324101637997592371449011938

00609025394840848271781943722884025331159521348610229029789827213532671

31629432532818915045306393916643 steve@192.168.1.19

4.Set the Optional Parameters – On the SSH Settings page, configure the optional parameters, including the authentication timeout, the number of retries, and the server key size.

5.Enable SSH Service – On the SSH Settings page, enable the SSH server on the switch.

6.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 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.

Notes: 1. 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.

2.The SSH server supports up to four client sessions. The maximum number of client sessions includes both current Telnet sessions and SSH sessions.

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