topic RE: How to connect via ssh from router cisco in ExtremeSwitching (EXOS/Switch Engine)

How to connect via ssh from router cisco

Susana_Tovar — Wed, 18 Oct 2017 20:15:00 GMT

Hello All,

My ISP needs connect with switches extreme by SSH from rouert cisco since we want to maintain this connection as contingency.

These are logs the cisco router

RTT_BF_HC_ENVIGADO_PPAL#ssh 1.1.1.1

[Connection to 10.128.35.4 aborted: error status 0]
RTT_BF_HC_ENVIGADO_PPAL#
Sep 8 16:10:50.648: SSH CLIENT0: protocol version id is - SSH-2.0-4.1.2 SSH Secure Shell Toolkit
Sep 8 16:10:50.648: SSH CLIENT0: sent protocol version id SSH-2.0-Cisco-1.25
Sep 8 16:10:50.648: SSH2 CLIENT 0: send:packet of length 344 (length also includes padlen of 5)
Sep 8 16:10:50.648: SSH2 CLIENT 0: SSH2_MSG_KEXINIT sent
Sep 8 16:10:50.652: SSH2 CLIENT 0: ssh_receive: 424 bytes received
Sep 8 16:10:50.652: SSH2 CLIENT 0: input: total packet length of 424 bytes
Sep 8 16:10:50.652: SSH2 CLIENT 0: partial packet length(block size)8 bytes,needed 416 bytes,
maclen 0
Sep 8 16:10:50.652: SSH2 CLIENT 0: input: padlength 8 bytes
Sep 8 16:10:50.652: SSH2 CLIENT 0: SSH2_MSG_KEXINIT received
Sep 8 16:10:50.652: SSH2:kex: server->client enc:aes128-cbc mac:hmac-sha1
Sep 8 16:10:50.652: SSH2:kex: client->server enc:aes128-cbc mac:hmac-sha1
Sep 8 16:10:50.652: SSH2 CLIENT 0: hostkey algo not supported: client ssh-rsa, server ssh-dss
Sep 8 16:10:50.652: SSH CLIENT0: Session disconnected - error 0x00

RTT_BF_HC_ENVIGADO_PPAL#ssh 1.1.1.1

[Connection to 10.128.35.4 aborted: error status 0]
RTT_BF_HC_ENVIGADO_PPAL#ssh 1.1.1.1
Sep 8 15:54:52.497: SSH2 CLIENT 0: hostkey algo not supported: client ssh-rsa, ho log

RE: How to connect via ssh from router cisco

Jarek — Wed, 18 Oct 2017 22:03:00 GMT

Hi,

I think the problem is here -> SSH2 CLIENT 0: hostkey algo not supported: client ssh-rsa, server ssh-dss

What is the switch model and what firmware you have on it?

--
Jarek

RE: How to connect via ssh from router cisco

Susana_Tovar — Wed, 18 Oct 2017 22:26:00 GMT

Hello Jarek,

I have extreme switches X250, X450 with version 15.3.5.2 patch1-10 at switches X440, 460, 670 and BD8800 with a version 16.1.4.2 patch1-7.

Regards.

RE: How to connect via ssh from router cisco

Jarek — Wed, 18 Oct 2017 23:33:00 GMT

The problem is that on your cisco device you have newer ssh implementation than on EXOS.
And in newer version ssh-dss keys has been disabled.

I don't know if there is any change, but the upgrade was in 21.1 and 16.2

Please see -> https://community.extremenetworks.com/extreme/topics/with-new-openssh-client-7-1-no-normal-ssh-login...

Could you write, what do you want to achieve?
Maybe we can find another way/idea to help you?

--
Jarek