SSH v1.99 VS v2.0

johnlloyd_13 · ‎04-04-2012

hi all,

is there a really big difference between the two SSH versions? i initially thought that version 1.99 is "the" 2.0.

Router#show ip ssh

SSH Enabled - version 1.99

Authentication timeout: 120 secs; Authentication retries: 3

Router1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router1(config)#ip ssh version 2

Router1(config)#end

Router1#show ip

*Apr 5 10:11:02.123: %SYS-5-CONFIG_I: Configured from console by console

Router1#show ip ssh

SSH Enabled - version 2.0

Authentication timeout: 120 secs; Authentication retries: 3

darren.g · ‎04-04-2012

johnlloyd_13 wrote:

hi all,

is there a really big difference between the two SSH versions? i initially thought that version 1.99 is "the" 2.0.

Router#show ip ssh

SSH Enabled - version 1.99

Authentication timeout: 120 secs; Authentication retries: 3

Router1#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router1(config)#ip ssh version 2

Router1(config)#end

Router1#show ip

*Apr 5 10:11:02.123: %SYS-5-CONFIG_I: Configured from console by console

Router1#show ip ssh

SSH Enabled - version 2.0

Authentication timeout: 120 secs; Authentication retries: 3

SSH version 1.99 is merely an indication that the server supports both SSH version 2 *and* SSH version 1.

It's not really a version, as such, but an indication of backward compatibility.

See

http://en.wikipedia.org/wiki/Secure_Shell

By seting your SSH config to V2, you're disabling V1 backward compatibility (not necesarily a bad thing, given V1's well-known and documented security holes).

Cheers.