Cant SSH2 to Extreme switches via Ubuntu

[Marvell_Kay]

We recently enable SSH2 in our environment. I am able to SSH to Cisco switches without any issue but can not to any Extreme switch. I can login to them fine via teraterm/secureCRT but not via Ubuntu.

I have a Ubuntu 14.04 machine. Here is what I am getting:

ssh admin@extreme_switch.com
ssh_exchange_identification: read: Connection reset by peer

With -v for more info:

ssh -v admin@extreme_switch.com
OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to extreme_switch.com [10.10.0.99] port 22.
debug1: Connection established.
debug1: identity file /home/admin1/.ssh/id_rsa type -1
debug1: identity file /home/admin1/.ssh/id_rsa-cert type -1
debug1: identity file /home/admin1/.ssh/id_dsa type -1
debug1: identity file /home/admin1/.ssh/id_dsa-cert type -1
debug1: identity file /home/admin1/.ssh/id_ecdsa type -1
debug1: identity file /home/admin1/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/admin1/.ssh/id_ed25519 type -1
debug1: identity file /home/admin1/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.8
ssh_exchange_identification: read: Connection reset by peer

Any idea why I can not login to Extremes?

Thanks
Zohaib

[Stephane_Grosj1]

Are you using openssh from ubuntu?

Your issue (with 15.7 EXOS version) is definitely related to the upgrade of openssh, and the legacy keys being disabled by default. The link from Frank is the solution.

For 22.x code, this is not necessary. I see you have a debug EXOS release. Why?

[Marvell_Kay]

I am getting this:

Unsupported KEX algorithm "+diffie-hellman-group1-sha1"
command-line line 0: Bad SSH2 KexAlgorithms '+diffie-hellman-group1-sha1'.

[Bernhard_Gruenw]

Hi,
after Ubuntu Update to 17.x I can't ssh to Extreme Switches (formerly Enterasys).
This helps for me:

ssh -o KexAlgorithms=+diffie-hellman-group1-sha1 admin@

or this options to an X450:

ssh -o HostKeyAlgorithms=+ssh-dss admin@

Regards,
Bernhard

[davidj_cogliane]

{Run update} should only be needed if the stack has not been booted since the code was loaded.

Also, to clarify if your switches are stacked, you only need to enable ssh on the master.

[Andrew_Imam]

Hi Zohaib,

For EXOS 15.7.2.9 you need to run the following commands to activate SSH on each switch:
- run update
- enable ssh2 vr all

For EXOS 22.2.1.5-P1-4 you need to run the following commands to activate SSH on each switch:
- enable ssh2 vr all

You can then run the "show management" command, check under the "SSH" heading that SSH is enabled and the key is valid.

Please let us know if you have any other questions.
Thank you.

Best regards,
Andrew