topic Can not open a terminal window from XMC to one device and not backing up this one device in ExtremeSwitching (EXOS/Switch Engine)

Can not open a terminal window from XMC to one device and not backing up this one device

sparkytcc — Tue, 05 Dec 2023 01:19:32 GMT

Hi All,
I am successfully backing up multiple Extreme switches. However one switch will not backup. Says Auth failure in server.log when I turn on verbose for scripting.

When I manually test with the credentials I can log in fine using the SSH credentials. I can also log in fine to the switch over ssh with my credentials (both radius). when I manually try a terminal when right click device it fails to connect. Log locally on switch reports successful though.

Ie, Login passed for user <blank> through ssh

From Log on XMC

auth methods: publickey, password,

authentication failure

Re: Can not open a terminal window from XMC to one device and not backing up this one device

FredrikB-NN2 — Wed, 06 Dec 2023 10:01:18 GMT

Can you do a normal SSH from the XMC server to the switch, that is, via the OS on that server? It may be that SSH is disabled or the keys have been messed up (not uncommon). If this is a Linux server just SSH to it and SSH from that login to the switch. If Windows, RDP to it and try to connect to the switch using PuTTY or similar. Check this in the switch:

sw01.1 # show management

[Skip a lot of lines...]

SSH access : Enabled (Key valid, tcp port 22 vr all)

If the SSH key is not valid, you need to generate a new one.

Re: Can not open a terminal window from XMC to one device and not backing up this one device

sparkytcc — Wed, 06 Dec 2023 20:04:36 GMT

Thanks for the reply.

I can open the terminal for over a 100 other switches from the XMC. So thinking no need to test from linux XMC.
Ssh keys is valid, thanks for that.

Re: Can not open a terminal window from XMC to one device and not backing up this one device

FredrikB-NN2 — Thu, 07 Dec 2023 14:40:18 GMT

I would still verify an SSH from the Linux OS to this switch. Can XMC read the switch SNMP wise? Could it be a problem with the routing table in the switch (if the management network is routed between XMC and the switch)? Is the switch IP in the correct subnet? Do you run OSPF or anything fancy on the management VLAN or is it a plain L2 VLAN?

You said: "I can also log in fine to the switch over ssh".

Is that from another computer? Can you SSH to the switch from another switch?

Re: Can not open a terminal window from XMC to one device and not backing up this one device

sparkytcc — Mon, 18 Dec 2023 00:10:26 GMT

I can ssh from the Cli of Linux XMC. The credentials that XMC use also worked. Its running 16.2.2.4 so it definately needs an upgrade.

Re: Can not open a terminal window from XMC to one device and not backing up this one device

FredrikB-NN2 — Mon, 18 Dec 2023 14:12:58 GMT

I wonder if XMC requires more secure cryptos than the CLI SSH. I'll see if I can find out how to tell if that is the case. Can you check the logs in the switch?

Re: Can not open a terminal window from XMC to one device and not backing up this one device

sparkytcc — Tue, 19 Dec 2023 18:52:14 GMT

Sorry Clicked Accepted as solution as I thought it was the reply button.
I would have to turn debug on i reckon as the logs are quiet on anything to do with ssh2. I would have thought other switches would fail also, and we have over a 100 working fine.

Re: Can not open a terminal window from XMC to one device and not backing up this one device

Stefan_K_ — Tue, 02 Jan 2024 13:33:18 GMT

Are other switches on the same firmware? You can check different switches with nmap to see if there is a difference in the SSH Ciphers:

nmap -sV -p 22 --script ssh2-enum-algos <ipaddress of switch>