[SOLVED] ssh failure after upgrade

AndrewZ

Successfully upgraded to 2.4.5 yesterday but today noticed that I cannot access my router via ssh:
on the client:

Received disconnect from 192.168.x.x port 22:2: Too many authentication failures
Disconnected from 192.168.x.x port 22

in the router log:

Disconnecting authenticating user root 192.168.x.x port 51602: Too many authentication failures [preauth]
error: maximum authentication attempts exceeded for root from 192.168.x.x port 51602 ssh2 [preauth]
user root login class [preauth]

ssh port is not open to outside world. Please advise how to recover.

jimp

It says right in the error that the authentication is failing. So you are using the wrong password. You could reset the admin account password in the GUI and see if that helps.

AndrewZ

Sorted out. The issue is not related to the password itself as the error occurs even before the user get a chance to enter his password.
The fix is to use either option from -o PreferredAuthentications=password -o PubkeyAuthentication=no or corresponding options in .ssh/config , this will prevent the client from offering the server all the keys it has available.
I'm curious while that never happened before, as nothing changed on the user side.