Filter
Top Products
CLI (Command Line Interface)
177
NXA-ENET24 - Software Management Guide
The SSH server on this switch supports both password and public key authentication.
If password authentication is specified by the SSH client, then the password can be authenticated
either locally or via a RADIUS or TACACS+ remote authentication server, as specified by the
authentication login command (see page 199).
If public key authentication is specified by the client, then you must configure authentication keys
on both the client and the switch as described in the following section.
Note that regardless of whether you use public key or password authentication, you still have to generate
authentication keys on the switch and enable the SSH server.
To Use the SSH Server
1.
Generate a Host Key Pair – Use the ip ssh crypto host-key generate command (see page 179) to create
a host public/private key pair.
2. Provide Host Public Key to Clients – Many SSH client programs automatically import the host public
key during the initial connection setup with the switch. Otherwise, you need to manually create a known
hosts file on the management station and place the host public key in it. An entry for a public key in the
known hosts file would appear similar to the following example:
10.1.0.54 1024 35 15684995401867669259333946775054617325313674890836547254
15020245593199868544358361651999923329781766065830956 10825913212890233
76546801726272571413428762941301196195566782 59566410486957427888146206
519417467729848654686157177393901647793559423035774130980227370877945452408397
1752646358058176716709574804776117
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 172.) 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
055536161631051775940838686311092912322268285192543746031009371877211996963178
136627741416898513204911720483033925432410163799759237144901193800609025394840
848271781943722884025331159521348610229029789827213532671316294325328189150453
06393916643 steve@192.168.1.19
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 (see page 178) 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.
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.
This section describes the commands used to configure the SSH server. However, note that you also need to
install a SSH client on the management station when using this protocol to configure the switch.
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.