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).
For example:
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[14924]: debug1: server_input_channel_req: channel 0 request [email protected] reply 0
Jul 4 xxxxxxx hostname sshd[14924]: debug1: session_by_channel: session 0 channel 0
Jul 4 xxxxxxx hostname sshd[14924]: debug1: session_input_channel_req: session 0 req [email protected]
Correspondingly on the client (macOS), I see this with ssh -vvv hostname:
debug1: Requesting authentication agent forwarding.
debug2: channel 0: request [email protected] 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.
Thanks
r.
screenortmuxsession, or is the variable set by the user's shell's startup files?