Is this what's failing for you?
Actually, it is weird. If I have my "normal" ssh keys loaded in
the agent, I can login just fine and get the password prompt:
tomh> ssh -l root fed23i
Enter passphrase for key '/home/tweety/.ssh/id_dsa':
root@fed23i's password:
Last login: Fri Jan 22 14:58:15 2016 from 10.134.30.143
[root@fed23i ~]# exit
logout
Connection to fed23i closed.
But when I add a couple of additional keys for the "test"
user we have on all the virtual machines, this happens:
tomh> add-nvtest
Identity added: /tmp/nvtkey21416/nvtest-rsa (/tmp/nvtkey21416/nvtest-rsa)
Identity added: /tmp/nvtkey21416/nvtest-dsa (/tmp/nvtkey21416/nvtest-dsa)
tomh> ssh -l root fed23i
Received disconnect from 192.168.118.167: 2: Too many authentication failures
Disconnected from 192.168.118.167
tomh> ssh-add -l
2048 SHA256:L09nWkcTbR4PmWmD/q6VJmjnwuKCtUHFaPN7xCRcwvM /home/tweety/.ssh/id_rsa (RSA)
1024 SHA256:1cKg/sJMH7TrWctSWky0hLO2PaxRVFfyddsqJQEqg0o /home/tweety/.ssh/id_dsa (DSA)
521 SHA256:/9Zg1JTdgpGwGpTCnLcbRXpuwFmt6P1gzXRcNQjEgLw /home/tweety/.ssh/id_ecdsa (ECDSA)
256 SHA256:vI83jQzZhfvTtZKEmgZiXUS/0te3dS1ew5vt16K38A8 tweety@tomh (ED25519)
1024 SHA256:YD5FOdt2WnvYH7AJ5VDIrJEwJm0MV0g1WtQAlQXXHSo /tmp/nvtkey21416/nvtest-rsa (RSA)
1024 SHA256:2J62l08cX62jDElLNk2qonCH8knistaEXJg+ayb6uPw /tmp/nvtkey21416/nvtest-dsa (DSA)
Does it maybe try every key and decide there are too many
that don't work when I go over a certain number?