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Cisco 3550-PWR SSH problem

Answered Question
Mar 24th, 2014
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I'm struggling to make SSH work on Cisco 3550-PWR router.

 

It has SSH 1.5/1,9 and complains to generate 768-bit key when I try to activate SSH 2. Even after I generate the keys, it still complains.

 

I'm able to SSH in using 1.5/1.9 but not 2 yet.

 

It's been a while since I've done R&S and could use a little help.

 

Thanks.

Correct Answer by Richard Burts about 3 years 4 months ago

It is good to know that SSH 1 works. This output

SSH Enabled - version 1.99

usually indicates that the device will accept both SSH 1 and SSH 2. So I am puzzled why SSH 2 is not working. In the original post you tell us "complains to generate 768-bit key when I try to activate SSH 2". I am not sure what that is about. Can you tell us what modulus was used to generate the SSH/RSA keys?

 

What happens if you generate new SSH/RSA keys and specify modulus 2048?

 

HTH

 

Rick

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Overall Rating: 5 (1 ratings)
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AFROJ AHMAD Mon, 03/24/2014 - 22:56
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  • Cisco Employee,

Hi ,

 

share the outputs from the : "debug ip ssh " command

 

what is the version of code you are running ?

 

do you see  "no exec" configured under his vty lines.  if yes remove it and then try again

 

Thanks-

Afroz

***Ratings Encourages Contributors ***

sendalot7 Tue, 03/25/2014 - 06:40
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Cisco IOS Software, C3550 Software (C3550-IPBASEK9-M), Version 12.2(44)SE6, RELEASE SOFTWARE (fc1)

I don't see any output from "debug ip ssh."

SSH1/1.5/1.9 works but not 2, can't activate it.

This is "show ip ssh"

SSH Enabled - version 1.99
Authentication timeout: 120 secs; Authentication retries: 3

Correct Answer
Richard Burts Thu, 03/27/2014 - 07:15
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It is good to know that SSH 1 works. This output

SSH Enabled - version 1.99

usually indicates that the device will accept both SSH 1 and SSH 2. So I am puzzled why SSH 2 is not working. In the original post you tell us "complains to generate 768-bit key when I try to activate SSH 2". I am not sure what that is about. Can you tell us what modulus was used to generate the SSH/RSA keys?

 

What happens if you generate new SSH/RSA keys and specify modulus 2048?

 

HTH

 

Rick

sendalot7 Thu, 03/27/2014 - 07:21
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Not sure what happened but after a restart and some miralce, SSH-2 not works.

I created 768 bit key bunch of times, etc.

Thanks!

Richard Burts Thu, 03/27/2014 - 07:54
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I am glad to know that SSH 2 has started to work. Sometimes a restart will get things synced up and working that had been somehow out of sync before. Perhaps it was something like that. Thank you for using the rating system to mark this question as answered.

 

HTH

 

Rick

vishal vyas Wed, 03/26/2014 - 17:59
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try to add command under line vty 

line vty 0 4

tranport input ssh

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