SSH authentication issues

[ohai89]

Hi,

I'm having an issue in using nornir_scrapli to connect to a vIOS router.

I can use the same nornir config.yaml listing dst IP and credentials to connect and manage the vIOS using netmiko & napalm.
It's only nornir_scrapli that keeps returning authentication failed / ssh timeout.

I'm using the same Ubuntu 20.04.4 LTS server to run all these, with a separate venv for all three (scrapli/netmiko/napalm).

For some reason scrapli keeps throwing me 'scrapli.exceptions.ScrapliTimeout: timed out during in channel ssh authentication'.

From 'debug ip ssh' on the vIOS router I see that scrapli SSH session is "Using method = none"
Immediately before tested netmiko shows "Using method = password" instead.

Scrapli:
*Mar 2 13:58:01.499: SSH1: sent protocol version id SSH-2.0-Cisco-1.25
*Mar 2 13:58:01.509: SSH1: protocol version id is - SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.4

Working netmiko:
*Mar 2 13:57:36.740: SSH1: sent protocol version id SSH-2.0-Cisco-1.25
*Mar 2 13:57:36.750: SSH1: protocol version id is - SSH-2.0-paramiko_2.9.2

I wonder if I'm missing some ssh option for Scrapli that should be used here.
Any pointers?
I can provide full ssh debugs if required.

Scrapli traceback below:

Traceback (most recent call last):
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/nornir/core/task.py", line 99, in start
r = self.task(self, **self.params)
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/nornir_scrapli/tasks/core/send_command.py", line 36, in send_command
scrapli_conn = task.host.get_connection("scrapli", task.nornir.config)
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/nornir/core/inventory.py", line 494, in get_connection
self.open_connection(
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/nornir/core/inventory.py", line 546, in open_connection
conn_obj.open(
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/nornir_scrapli/connection.py", line 98, in open
connection.open()
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/scrapli/driver/base/sync_driver.py", line 86, in open
self.channel.channel_authenticate_ssh(
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/scrapli/decorators.py", line 280, in decorate
return self._multiprocessing_timeout(
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/scrapli/decorators.py", line 340, in _multiprocessing_timeout
self._handle_timeout()
File "/home/iaho/cbt/scrapli/lib/python3.8/site-packages/scrapli/decorators.py", line 316, in _handle_timeout
raise ScrapliTimeout(self.message)
scrapli.exceptions.ScrapliTimeout: timed out during in channel ssh authentication

[carlmontanari]

Almost certainly related to this.

conn.channel._auth_password_pattern = blah as mentioned in that thread, or use a different transport, or set a sane banner.

[ohai89]

Yes, that would be the case.
Confirmed by removing login banner altogether, now access works with Scrapli as well.

I still need to research how to actually change the transport.