Rsa Authentication Process; Password Authentication Process; Ssh Configuration - Avaya G250 Administration

Accessing the Avaya G250/G350 Media Gateway
Establishing an SSH session can be done by RSA authentication, or Password authentication.
To determine which of these ways is used on your G250/G350, use the show ip ssh
command.

RSA authentication process

The G250/G350 generates a key of variable length (512-2048 bits) using the DSA
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encryption method. This is the private key.
The G250/G350 calculates an MD5 Hash of the private key, called a fingerprint (the public
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key). The fingerprint is always 16 bytes long. This fingerprint is displayed.
The G250/G350 sends the public key (the fingerprint) to the client computer. This public
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key is used by the client to encrypt the data it sends to the G250/G350. The G250/G350
decrypts the data using the private key.
Both sides negotiate and must agree on the same chipper type. The G250/G350 only
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supports 3DES-CBC encryption. The user on the client side accepts the fingerprint. The
client maintains a cache containing a list of fingerprints per server IP address. If the
information in this cache changes, the client notifies the user.
The client chooses a random number that is used to encrypt and decrypt the information
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sent.
This random number is sent to the G250/G350, after encryption based on the G250/
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G350's public key.
When the G250/G350 receives the encrypted random number, it decrypts it using the
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private key. This random number is now used with the 3DES-CBC encryption method for
all encryption and decryption of data. The public and private keys are no longer used.

Password authentication process

Before any data is transferred, the G250/G350 requires the client to supply a user name and
password. This authenticates the user on the client side to the G250/G350.

SSH Configuration

Use the ip ssh command to enable SSH authentication. Use the no form of this command to
disable the SSH server which disconnects all active SSH sessions. By default, SSH is enabled.
Use the crypto key generate dsa command to generate an SSH host key pair.
Use the show ip ssh command to display SSH configuration information and information
about any active SSH sessions.
Use the disconnect ssh command to disconnect an existing SSH session.
46 Administration for the Avaya G250 and Avaya G350 Media Gateways