Can't connect to the switch with AsyncSSH with "auth_strict_key" = False option

Describe the bug When you have in Scrapli connection options “auth_strict_key” = False for AsyncSSH transport, there is a known bug for AsyncSSH with “known_hosts”=None https://github.com/ronf/asyncssh/issues/323 When that happens AsyncSSH send all his “host_key_algs” to the host and that’s more than 20 of them and there are some hosts that just disconnects on such a many number of host keys algs received.

To Reproduce

1. When you have in connection options for AsyncSSH tranport “auth_strict_key” = False

conn_dict["auth_strict_key"] = False
conn = AsyncGenericDriver(**conn_dict)

1. Your switch can’t comprehend so much “host_key_algs” sent at him.
2. Switch closes connection on key exchange.

Expected behavior Scrapli connects through AsyncSSH.

How to fix So, as a workaround i added “server_host_key_algs=[‘ssh-rsa’]” to scrapli\transport\plugins\asyncssh\transport.py lines 113-127

        try:
            self.session = await asyncio.wait_for(
                connect(
                    client_keys=self.plugin_transport_args.auth_private_key,
                    password=self.plugin_transport_args.auth_password,
                    preferred_auth=(
                        "publickey",
                        "keyboard-interactive",
                        "password",
                    ),
                    server_host_key_algs=['ssh-rsa'],
                    **common_args,
                ),
                timeout=self._base_transport_args.timeout_socket,
            )

It works for me now, but i think for the general Scrapli use it must some more clever solution. Something like:

1. Check if “auth_strict_key” is False.
2. Add “server_host_key_algs=[‘ssh-rsa’]” to the list of AsyncSSH transport options.

OS (please complete the following information):

• OS: Debian 10.7
• scrapli version: 2021.07.30

[carlmontanari]

Since I got rid of the “known issues” section a while back since (thankfully) there were not many, and also because I kept forgetting about it and so it was never updated/contained outdated things… I just added this to the transport plugin docstrings. Hopefully that ++ this issue will make this searchable enough for folks in the future!

Thanks again for your work on this!

Carl

[carlmontanari]

looks like i’ve found a solution that will not require any code changes

I like the way you think! 😁

I will leave this open to make sure I remember to document this this weekend! Thanks again for all the help!

Carl