Create ssh keys
mkdir .ssh
cd .ssh
ssh-keygen -t rsa
should produce:
~/.ssh/id_rsa <---- private key
~/.ssh/id_rsa.pub <---- public key
Add to keyring to save passwords for you
ssh-add ~/.ssh/id_rsa
Create ~/.ssh/config
# Public
Host github.com-pub
HostName github.com
User git
IdentityFile ~/.ssh/github_public
# External
Host github.com-ext
HostName github.com
User git
IdentityFile ~/.ssh/github_external