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SSH connection fails - server refused authentication protocol


I have a 3845 router. 

  • Setup SSH Version 2
  • generated rsa keys (1024)
  • set login local
  • transport input ssh and telnet is enabled since I can't get ssh connection working

When I connect using SSH, I get the following error.

server refused authentication protocol.

22 Replies 22


another idea:

did you earlier connect to another device over ssh which had either the same ip address or hostname?

maybe this a key issue. ttermpro2 knows the old key and tries to exchange with a different machine.

of course this must fail. the same comes to light when the ssh keypair itself is replaced on the router.

try to find the known_host key cache on your ttermpro and either clear it or remove the entries concerning

the particular IP or hostname.

the easiest way would be a connection attempt from a different system, best a Linux based.

No go on the Linux systems...I have none.

I tried on a new host, never to have connected to the router via SSH or Telnet before on the host.  I saw the message, do you want to use this 2048, no way of validating, click yes to save it and use it.  Clicked yes.  Still get server refused user authenticaiton protocol.

this is somewhat strange.

if you wish, you may send me the public IP address of your router and I can then open a SSH session from my

Solaris Worksation and analyze the traffic packets with tcpdump and openssl client. We then see more what is

going wrong.

mail me the IP at: E605  ~a~T* LIVE_dot_DE



I got a new program, SecureCRT and can now get connected via SSH.  Excellent instructions, thank you David! 

your are most welcome..

great to see you got your ssh access back.




i am facing the same issue today and took me while to fix up. 

this is the command i re-typed and make SSH work. 

crypto key generate rsa general-keys modulus 1024

not really sure why, but that how I fixed.




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