Host key verification failed.

Either remove the offending entry with:

ssh-keygen -R [IP/HOSTNAME]

or open the the known_hosts file, and remove the entry manually:

nano ~/.ssh/known_hosts

Important Keep in mind that this is an important security measure. The fact that this fails means that you have previously connected to a computer at the same address with a different finger print. This means that either the machine on the other end has changed significantly (reformatted) or has been replaced.

Unless you are aware of, or made the change, you probably shouldn’t ignore this error.

SSH Reverse Runnel

To access a computer behind firewall, without public ID, SSH forwarding is useful.

Assuming 3 components:

  • YC: Your computer
  • PI: A computer with a public IP and a user tunnel
  • RC: The computer you are trying to access; user panther

On RC run:

ssh -R 2222:localhost:22 tunnel@ # PI IP address

On YC run:

ssh -At tunnel@ ssh panther@localhost -p 2222

You should now be connected.

SSH ProxyJump

You can also use ProxyJump on YC; run:

ssh -J tunnel@ panther@localhost -p 2222 -f -N


ssh -p 2222 -o ProxyJump=root@ panther@localhost


$ ssh-copy-id -p 2222 -o ProxyJump=tunnel@ panther@localhost
/run/current-system/profile/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/run/current-system/profile/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
panther@localhost's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh -p '2222' -o 'ProxyJump=root@' 'panther@localhost'"
and check to make sure that only the key(s) you wanted were added.

PantherX & (unofficial) GNU Guix Wiki.

Last update: 2024-04-21 10:28:03 +0000 | Apache-2.0

Inspired by the excellent Arch Linux Wiki