If you were used to storing your ssh keys in your Keychain, you may have noticed that your ssh agent forwarding wasn’t working when you updated to macOS Sierra.
According to jirsbek on GitHub:
ssh-add -K in macOS Sierra no longer saves SSH keys in OS’s keychain. As Apple Developer stated: “That’s expected. We re-aligned our behavior with the mainstream OpenSSH in this area.”
I’m actually ok with the change in behavior. To resolve it, call ssh-add -A to add your identities into your ssh-agent. I’m doing that as part of my .bashrc (though I haven’t rebooted yet, I assume it’ll work).
(Via jirsbek on GitHub.)