I had to connect to our servers to perform daily maintenance, but suddendly I was getting error:
ssh arc [...] Received disconnect from zzz.zzz.zzz.zzz port 1234:2: Too many authentication failures # and also sign_and_send_pubkey: signing failed: agent refused operation
I was able to login using password, with:
ssh -p 1234 -i ~/.ssh/id_rsa_id.pub -o PubkeyAuthentication=no root@$IP
But I was unable to use our keys.
Then, I realised the problem was coming from the use of
gnome-keyring doesn’t always handle specific formats of SSH keys correctly. Unfortunately, gnome-keyring was trying to handle all SSH key usage, preventing the keys from working.
you can confirm that gnome-keyring is at fault on your system by added SSH_AUTH_SOCK=0 in front of the ssh command as follows:
SSH_AUTH_SOCK=0 ssh arc
In order to fix the gnome-keyring interference, the SSH Key Agent will have to be disabled from the startup applications.
Also, the current instance must be terminated (to avoid rebooting).
PS: a useful page.