Why doesn't my SSH key work for connecting to github?

The GitHub ssh setup mentions testing your GitHub connection with:

$ ssh -T [email protected]

That follow the ssh uri syntax (also illustrated in "this answer").

But you did:

ssh github.com

(without any user). In that case, ssh reverts to the SCP syntax, which relies on a ~/.ssh/config file, with a section "github.com", to list:

the user
the hostname
(and optionally the public key location, but by default it will try ~/.ssh/id_rsa.pub)

To change it to a regular SSH URL, don't edit directly your .git/config file, as shown below.
Use the command git remote set-url:

git remote set-url origin [email protected]:username/repo.git

I had a similar problem, github did not use my SSH key. I always had to enter my username and password.

I've been looking at .git/config, under [remote "origin"] there was:

    url = http://github.com/path/to/repository

    url = https://github.com/path/to/repository

I changed the line into

    url = ssh://[email protected]/path/to/repository

and then it worked.

After creating a config file (~/.ssh/config) it worked. This is what I had to put in it:

Host github.com
User git
Port 22
Hostname github.com
IdentityFile ~/.ssh/id_rsa
TCPKeepAlive yes
IdentitiesOnly yes

Thanks to @VonC for leading me to there in the comments.

I don't get why I never needed this before though.

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