How to get Leopard ssh agent to work if you previously used "SSH Agent" App

Question

Hi Everyone,
I had previously been using the *SSH Agent* application from http://www.phil.uu.nl/~xges/ssh/ and wanted to get rid of it and use the built-in support for ssh-agent in Leopard.
However, it didn't work. Doing "env | grep SSH" it would show /tmp/501/nl.uu.phil.SSHAgent.socket and ssh'ing from a terminal window would request your passphrase every time. Executing ssh-agent would say "no agent is running." Even deleting the *SSH Agent* app and rebooting, it would still have this phil socket.
The solution is to use terminal, go to your home directory, cd to .MacOSX and look and see if there's an environment.plist file. In there will be some XML to set this persistent string for SSHAUTHSOCK. You need to take that out. If there's other stuff in the file, like a CVSHOME entry, hand-edit the XML to take out the SSHAUTHSOCK entry. (How to do that is beyond the scope of this post.) If the only thing is that entry, just delete the environment.plist file.
Afterwards, reboot, or maybe just log out and log back in, open a terminal window, and you should be able to ssh out and the system will start ssh-agent behind your back and find your .ssh/id_dsa file or whatever.
Karl

Answer 1

The man page for ssh-agent provides the following documentation:
-a bind_address
Bind the agent to the unix-domain socket bind_address. The
default is /tmp/ssh-XXXXXXXXXX/agent.<ppid>.
The system ssh-agent's startup arguments are in /System/Library/LaunchAgents/org.openbsd.ssh-agent.plist so you could add something like the following to array that defines the ProgramArguments:
<string>-a</string>
<string>/whatever/the/path/is/that/you/want/to/have</string>
Note that since these mods are being done in /System, they could be wiped out by any system update. You could try making a copy of the file and putting the copy in /Library/LaunchAgents; perhaps files in that directory take precedence over files in /System. Certainly, stuff in /Library shouldn't be wiped out by a system update, though.