HP procurve 2500 사용자 설명서

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Enhancements in Release F.04.08
Configuring Secure Shell (SSH)
SSH Client Contact Behavior. 
At the first contact between the switch and an SSH client, if you 
have not copied the switch’s public key into the switch, your client’s first connection to the switch 
will question the connection and, for security reasons, give you the option of accepting or refusing. 
As long as you are confident that an unauthorized device is not using the switch’s IP address in an 
attempt to gain access to your data or network, you can accept the connection. (As a more secure 
alternative, you can directly connect  the client to the switch’s serial port and copy the switch’s public 
key into the client. See the Note, below.)  
N o t e
When an SSH client connects to the switch for the first time, it is possible for a "man-in-the-middle" 
attack; that is, for an unauthorized device to pose undetected as the switch, and learn the usernames 
and passwords controlling access to the switch. You can remove this possibility by directly 
connecting the management station to the switch’s serial port, using a 
show command to display the 
switch’s public key,  and copying the key from the display into a file. This requires a knowledge of 
where your client stores public keys, plus the knowledge of what key editing and file format might 
be required by your client application. However, if your first contact attempt between a client and 
the switch does not pose a security problem, this is unnecessary.
To enable SSH on the switch. 
1.
2.
Execute the 
ip ssh command.
To disable SSH on the switch, do either of the following:
Execute 
no ip ssh.
Zeroize the switch’s existing key pair. (page 86).
Syntax:
[no] ip ssh 
Enables or disables SSH on the switch
[key-size < 512 | 768 | 1024 >]
The size of the internal, automatically generated key
the switch uses for negotiations with an SSH client. A
larger key provides greater security; a smaller key
results in faster authentication (default: 512 bits).
See the following Note.
[port < 1-65535 | default >]
The IP port number for SSH connections 
(default:  22)
.
Important:
 See the following "Note" on port number.
[timeout < 5 - 120 >]
The SSH login timeout value (default: 120 seconds)
.