Some Mac users have found that SSH no longer works on their Mac since they have been updated to macOS Ventura 13 or newer. They usually see an error message when they try to ssh to another server along the lines of “no matching host key type found. Their offer: ssh-rsa“.
The obvious reason for this problem is that the version of OpenSSH that ships with macOS Ventura disables RSA signatures by default, so you can solve the problem by either using a more secure hash, or by simply allowing RSA signatures. We'll show you how to do the latter.
We are going to use nano because it is easy and user-friendly, but you can also use vi/vim or any other text editor of your choice.
We are going to modify the ssh_config file to allow RSA host key again, here is how to do this:
- Open the Terminal (via Spotlight or via the Utilities folder) and enter the following command string:
sudo nano /etc/ssh/ssh_config
You have to authenticate with the admin password.
2. Scroll all the way to the bottom of the ssh_config file, then add the following lines to the bottom of ssh_config:
HostkeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa
3. Hit Control+O to save, and Control+X to exit.
Your SSH problem should now be solved, we thought it would be super logical to share this information with you.
