I am struggling to diagnose why one particular server does not honour the agent forwarding I have setup.
From client (macOS) I can
ssh -A to any number of servers and on them can see that
SSH_AUTH_SOCK is set, and
ssh-add -L shows my key.
On one particular host this does not work. When I login
SSH_AUTH_SOCK is set, but
ssh-add -L says "
this agent has no identities."
Firstly my sense is that if
SSH_AUTH_SOCK is set then the agent forwarding has worked in the sense that
AllowAgentForwarding is enabled on client and server (which I've checked to be true).
On the problematic host:
$ echo $SSH_AUTH_SOCK /tmp/ssh-ZpxzssfdPuZq/agent.14304 $ ssh-add -l This agent has no identities.
And for the ssh server on that host I find these mentions of 'agent' in the sshd logs when
DEBUG3 is set:
Jul 4 xxxxxxx hostname sshd: debug1: server_input_channel_req: channel 0 request email@example.com reply 0 Jul 4 xxxxxxx hostname sshd: debug1: session_by_channel: session 0 channel 0 Jul 4 xxxxxxx hostname sshd: debug1: session_input_channel_req: session 0 req firstname.lastname@example.org
Correspondingly on the client (macOS), I see this with
ssh -vvv hostname:
debug1: Requesting authentication agent forwarding. debug2: channel 0: request email@example.com confirm 0 debug3: send packet: type 98
So that covers all the options and scenarios my knowledge of ssh and its config comprise. So I am asking what further steps I might do to source the problem, or what I'm missing more obviously.