Issue SSH

Unanswered Question
Jun 3rd, 2009

I did upgrade to version of IOS cat4000-i9k91s-mz.122-18.EW2.bin to cat4500-entservicesk9-mz.122-52.SG.bin at a catalyst 4507r engine IV.

Before i could to execute:

ssh, without problem.

But after upgrade i can't do that.

In catalyst 4507r:


router_4507r#sh ip ssh

SSH Enabled - version 1.99

Authentication timeout: 120 secs; Authentication retries: 3


[Connection to aborted: error status 0]

In router remote:


Router_remote#sh ip ssh

SSH Enabled - version 1.99

Authentication timeout: 120 secs; Authentication retries: 3

I have this problem too.
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pesanchez2002 Wed, 06/03/2009 - 07:44

Hi thanks by your answer

I executed the command

ssh -l username

and receive the same message

[Connection to aborted: error status 0]

Edison Ortiz Wed, 06/03/2009 - 07:48

Can we see the complete configuration on both devices?

Can you ping ?

Can you verify you have enough VTY sessions available? (show users).



pesanchez2002 Wed, 06/03/2009 - 08:24


Yes i can do ping

I can do ssh connection with my Computer using putty in my computer without problem.

I have 3 possible connection vty:

line vty 0 2

session-timeout 3

access-class 51 in

exec-timeout 3 0

timeout login response 15

logging synchronous

transport input ssh

I had no problem to connect before carrying out the upgrade of IOS.

Edison Ortiz Wed, 06/03/2009 - 08:33

Then the problem can be IOS related. Try a earlier version than the one you currently have.



ahintzsche Tue, 11/02/2010 - 03:00

maybe it's still helpful. i had the same issue. check the version of ssh configured on

I have two switches (2950, same IOS etc), destination switch configured with ip ssh version 2. when trying to ssh from switch one to that it gives me error message, even though when showing ssh both seem to run ssh version 2 ok. But when I take the command out they connect on ssh 1.5.

So I guess you can either take the command out or put it in on the other switch (if supported).

Then you might have different switches altogether by now.

famfran13 Thu, 08/08/2013 - 15:58

I had a similar case:

Error reported by the customer:

Router2#ssh -l userID x.x.x.x

[Connection to x.x.x.x aborted: error status 0]


Enabled on x.x.x.x router:

conf t
crypto key generate rsa

Devices is reachable from Router2 now:

Router2#ssh -l userID x.x.x.x


andacn001 Fri, 11/29/2013 - 08:16

Your old IOS contains only the Server function for SSHv2.
You can´t operate as a client with this IOS when SSHv2 is enabled
With SSHv1 you can operate both as a server and as a client.
Your new IOS also offers only the same function of SSHv1 and SSHv2 like your old IOS
Still it is not possible with SSHv2 to operate as a client.

You need a newer IOS. The Cisco IOS Releases 15.0(2)SG (Catalyst 4500 Series Switch) contains Secure Shell SSHv2 Client and Server Support

You need a crypto key with at least 768 bit to enable SSHv2

for additional questions look here:

Check your current IOS features with the Cisco Feature Navigator:


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