Can no longer SSH into RM2 - "no matching host key type found. Their offer: ssh-rsa"

[jim9835]

@danielebruneo - thanks so much for your work to date, I've been using How-to-SSH-into-the-RM2 for a while without issue.

However, today I tried after updating my RM2 to the latest update, 2.10.2.356, and am now getting

Unable to negotiate with 10.11.99.1 port 22: no matching host key type found. Their offer: ssh-rsa

So am no longer able to SSH in to the RM2 and so can't install remarkable-hacks, which is a bit painful...

Can you help?

[Dirk Osburg]

Sounds like the ssh host key of your rm2 was changed by the update.

You have to delete the ssh host key which is cached/saved on your local machine.
On Linux systems this cache resides in ~/.ssh/known_hosts and the key can be remove with the following command
ssh-keygen -R <hostname/ip-of-your-rm2>

[jim9835]

Thanks for the quick response. I've had to clear known hosts before, but I seem to remember the error message being different.

Anyway, have tried your suggestion, a key has been removed from known_hosts, but am still getting the same error.

[jim9835]

I had a look online and found various suggestions. The one that has worked I found here:

https://askubuntu.com/questions/836048/ssh-returns-no-matching-host-key-type-found-their-offer-ssh-dss

This worked:

sudo nano /etc/ssh/ssh_config

add to new empty line:

HostKeyAlgorithms ssh-rsa,ssh-dss
PubkeyAcceptedKeyTypes ssh-rsa,ssh-dss

I didn't need to to reload/restart SSHd.

FYI - I have a Manjaro Linux OS

[Dirk Osburg]

Thanks for sharing the solution.

You can also set this ssh client option as command line paramter:
ssh -oHostKeyAlgorithms=+ssh-rsa root@<rm2_ip>

or set this option in the ssh user config file ~/.ssh/config

Host rm2
  HostName <rm2_ip>
  HostKeyAlgorithms=+ssh-rsa

btw. I think it might be sufficient if you would only ad ssh-rsa an not ssh-dss (because the latter is outdated and should be avoided).