SSH HostkeyAlgorithms and private key

A note for .ssh/config

The file should contain

HostkeyAlgorithms =+ssh-dss,ssh-rsa

Note the =+

I had received the following error earlier;

Unable to negotiate with xx.xx.xx.xx port 22: no matching host key type found. Their offer: rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519

and couldn't for the life of me understand why. Eventually tracing down the config file from above was missing the =+ and I'm assuming this meant is was only allowing ssh-dss,ssh-rsa and causing the error above.

Private Keys

In other news, if we wish to login to a box using a private key, we would normally do something like:

ssh -i path_to_key user@ip_address

We can also create a .ssh/config (600) file or amend it to include the details so that we can login with something like:

ssh host

As an example, we would add the below:

Host oracle
    HostName 192.168.254.121
    User opc
    IdentityFile ~/.ssh/oracle.key

where oracle would be the host name and the private key would be in .ssh/oracle.key

We can then do ssh oracle