Let's say I have a key for Github, along with other keys. I've added lots of keys to my ssh agent (
ssh-add -L returns lots of lines) at my home computer A. In my
.ssh/config I have set up which key to use with which host, so e.g.
ssh -T -vvv firstname.lastname@example.org 2>&1 | grep Offering
debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.github
Only one key is offered, as expected. But then ssh-ing to some host B with
ForwardAgent yes and repeating the same command, I get
debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.linode2 debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.helium debug1: Offering RSA public key: /Users/doxna/.ssh/id_rsa.github
meaning it tries all my keys. This is problematic since only a limited number of keys can be tried before servers return
Too many authentication failures. So I tried editing
.ssh/config on host B to include
Host github.com IdentityFile /Users/doxna/.ssh/id_rsa.github IdentitiesOnly yes
but then I get no key offerings, but rather
debug2: key: /Users/doxna/.ssh/id_rsa.github ((nil))
which I guess means that the key was not found(?) And after all, the key is located at my home computer A, not host B, so the question is how to refer to it at host B? Hope I managed to explain the question.