Verify host key with pysftp

Question

I am writing a program using pysftp, and it wants to verify the SSH host Key against C:\\Users\\JohnCalvin\\.ssh\\known_hosts.

Using PuTTY, the terminal

Answer 1

Cook book to use different ways of pysftp.CnOpts() and hostkeys options.

Source : https://pysftp.readthedocs.io/en/release_0.2.9/cookbook.html

Host Key checking is enabled by default. It will use ~/.ssh/known_hosts by default. If you wish to disable host key checking (NOT ADVISED) you will need to modify the default CnOpts and set the .hostkeys to None.

import pysftp
cnopts = pysftp.CnOpts()
cnopts.hostkeys = None
with pysftp.Connection('host', username='me', password='pass', cnopts=cnopts):
    # do stuff here

To use a completely different known_hosts file, you can override CnOpts looking for ~/.ssh/known_hosts by specifying the file when instantiating.

import pysftp
cnopts = pysftp.CnOpts(knownhosts='path/to/your/knownhostsfile')

with pysftp.Connection('host', username='me', password='pass', cnopts=cnopts):
    # do stuff here

If you wish to use ~/.ssh/known_hosts but add additional known host keys you can merge with update additional known_host format files by using .load method.

import pysftp
cnopts = pysftp.CnOpts()
cnopts.hostkeys.load('path/to/your/extra_knownhosts')
with pysftp.Connection('host', username='me', password='pass', cnopts=cnopts):
    # do stuff here