SSH: Unsupported option "rsaauthentication"

I have SSH set up (macOS 10.13) among others, with GitLab too, and when connecting to a different (NOT GitLab) server, I get the following error:

/Users/username/.ssh/config line 25: Unsupported option “rsaauthentication”

And this is what I have on line 25 (and a couple of lines around it) in my config file - it’s basically the GitLab ssh default config, according to the relevant doc:

23    Host
24    User git
25    RSAAuthentication yes
26    IdentityFile ~/.ssh/id_rsa_gitlab

I haven’t seen this error before, it started to show up only recently, although I cannot connect it with a recent event, maybe the upgrade to macOS 10.13, but I do not remember exactly, unfortunately.

The SSH connection I’m (successfully) making is to an Ubuntu server using a different SSH config and key.

I’m not sure, is this an issue on the Ubuntu server side or is it something on the GitLab side of things? I’m assuming Ubuntu, considering it’s not supposed to take that line into account at all (I’m also assuming that the server must run through the entire config file either way), at the same time my GitLab config is the only one using the RSAAuthentication option.

Note: the connection does go ahead successfully, so no issues there; I’m really just curious about this error (or warning).


I today had the same issue on my Windows 10 laptop. When googling I found this topic.
My other connection from an Ubuntu/Linux PC goes ahead without problems.
And the same setup for github works as expected, so to me it seems like an gitlab issue.

I just updated to git for windows 1.14.2

Just had the same issue. I found this forum post which points to the OpenSSH release notes. The latest release drops support for SSH protocol version 1, including RSAAuthentication.

That’s as far as I got. Don’t know what the fix is, and I don’t even know how my OpenSSH installation got updated.


You just need to replace RSAAuthentication yes with PubkeyAuthentication yes and the warning will be gone.


Yes, mixing @dougw’s answer above, and another article I found stating “RSAAuthentication is for SSHv1 keys, PubkeyAuthentication is for SSHv2 key” this seems to be the right answer. Thank you, @hans89

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Maybe someone should update then.

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