SSH-AGENT(1)

NAME
ssh-agent - SSH authentication agent

SYNOPSIS
ssh-agent [ -l ] factotum-service

DESCRIPTION
Ssh-agent presents factotum((4)) using the interface that ssh((1)) requires.

Once ssh-agent and factotum are running, the standard Unix SSH client can use ssh-agent (and, indirectly, factotum) to authenticate to remote systems using RSA or DSA keys.

Ssh accesses ssh-agent via a Unix socket named ssh-agent.socket in the name space directory (see intro((4))). Note that although the socket is posted in the name space directory, it is not for 9P conversations. Ssh expects the name of this socket to be in the environment as $SSH_AGENT_SOCK, and expects the agent to be running with process id $SSH_AGENT_PID. Ssh-agent prints shell commands to set these two variables before forking itself into the background. It is typically invoked inside a shell eval construct; see the examples below. The -e option causes ssh-agent to include export commands to put the variables into the environment of future programs.

If the -l option is given, ssh-agent lists the usable factotum keys in the standard SSH format, suitable for creating an authorized_keys file.

Ssh-agent connects to factotum by accessing factotum-service (default `factotum') in the current name space.

There is a Unix program called ssh-agent that manages SSH keys itself. Invoke this one with 9 ssh-agent; see 9((1)).

EXAMPLES
Assume factotum((4)) is already running and initialized with keys.

Start a new agent, copying the commands by hand:

        $ 9 ssh-agent -e
        SSH_AUTH_SOCK=/tmp/ssh-405795003d7ee27a/agent.4233;
        export SSH_AUTH_SOCK;
        SSH_AGENT_PID=4233;
        export SSH_AGENT_PID;
        $ SSH_AUTH_SOCK=/tmp/ssh-405795003d7ee27a/agent.4233;
        $ export SSH_AUTH_SOCK;
        $ SSH_AGENT_PID=4233;
        $ export SSH_AGENT_PID;
        $

Start the agent from sh((1)):

        $ eval `9 ssh-agent -e`
        $

Start the agent from rc((1)):

        % eval `{9 ssh-agent}
        %

Use the agent to connect to a remote system:

        % ssh tux
        tux% ^D
        %

SOURCE
/src/cmd/auth/ssh-agent.c

SEE ALSO
ssh((1)), rsa((1)), factotum((4))

BUGS
A surprise rather than a bug: ssh-agent connects to factotum on demand, so it can be started before factotum is running and need not be restarted just because factotum is.