Configuring Dsa Challenge-Response Authentication - Dell PowerConnect B-RX Configuration Manual

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Configuring SSH
The generate keyword places an DSA host key pair in the flash memory and enables SSH on the
device.
The zeroize keyword deletes the DSA host key pair from the flash memory and disables SSH on the
device.
By default, public keys are hidden in the running configuration. You can optionally configure the
device to display the DSA host key pair in the running configuration file entering the following
command.
BigIron RX# ssh show-host-keys
Syntax: ssh show-host-keys
To hide the public keys in the running configuration file, enter the following command.
BigIron RX# ssh no-show-host-keys
Syntax: ssh no-show-host-keys
Providing the public key to clients
If you are using SSH to connect to a BigIron RX from a UNIX system, you may need to add the
device's public key to a "known hosts" file; for example, $HOME/.ssh/known_hosts. The following
is an example of an entry in a known hosts file.
AAAAB3NzaC1kc3MAAACBAPY8ZOHY2yFSJA6XYC9HRwNHxaehvx5wOJ0rzZdzoSOXxbET
W6ToHv8D1UJ/
z+zHo9Fiko5XybZnDIaBDHtblQ+Yp7StxyltHnXF1YLfKD1G4T6JYrdH YI14Om
1eg9e4NnCRleaqoZPF3UGfZia6bXrGTQf3gJq2e7Yisk/gF+1VAAAAFQDb8D5cv
wHWTZDPfX0D2s9Rd7NBvQAAAIEAlN92+Bb7D4KLYk3IwRbXblwXdkPggA4pfdtW9v
GfJ0/RHd+NjB4eo1D+0dix6tXwYGN7PKS5R/FXPNwxHPapcj9uL1Jn2AWQ2dsknf+i/FAA
vioUPkmdMc0zuWoSOEsSNhVDtX3WdvVcGcBq9cetzrtOKWOocJmJ80qadxTRHtUAAACB
AN7CY+KKv1gHpRzFwdQm7HK9bb1LAo2KwaoXnadFgeptNBQeSXG1vO+JsvphVMBJc9HS
n24VYtYtsMu74qXviYjziVucWKjjKEb11juqnF0GDlB3VVmxHLmxnAz643WK42Z7dLM5
sY29ouezv4Xz2PuMch5VGPP+CDqzCM4loWgV

Configuring DSA challenge-response authentication

With DSA challenge-response authentication, a collection of clients' public keys are stored on the
device. Clients are authenticated using these stored public keys. Only clients that have a private
key that corresponds to one of the stored public keys can gain access to the device using SSH.
When DSA challenge-response authentication is enabled, the following events occur when a client
attempts to gain access to the device using SSH.
1. The client sends its public key to the BigIron RX.
2. The device compares the client's public key to those stored in memory.
3. If there is a match, the device uses the public key to encrypt a random sequence of bytes.
4. The device sends these encrypted bytes to the client.
5. The client uses its private key to decrypt the bytes.
6. The client sends the decrypted bytes back to the BigIron RX.
870 BigIron RX Series Configuration Guide
53-1001810-01