One of the small, but incredibly useful features for me in Leopard is that ssh-agent is automatically running for each user account. This relatively small change allows me to log into remote machines without entering my password each time.
Using the SOCKS proxy built into ssh, we're also able to setup a quick and easy secure tunnel. I wanted to check some sensitive information this morning, but I'm at a coffee shop that doesn't pass VPN traffic, so I quickly hacked together the following:
Setup a new Location in the Network System Preference Pane to configure the SOCKS proxy at 127.0.0.1, port 4088. This connects most Apple applications to the secure and encrypted tunnel.
Next, I configured ssh to automatically setup the SOCKS proxy whenever I type "ssh ford", which is an alias for my workstation back at the office.
# ~/.ssh/config
host ford
User mccune
HostName ford.math.ohio-state.edu
# Handle sleep/wake robustly with TCPKeepAlive
TCPKeepAlive no
Port 22
# DynamicForward is a SOCKS proxy server.
DynamicForward 4088
ForwardX11 no
With this configuration, I'm able to load my SSH public key into the ssh-agent running by default on Leopard, type "ssh ford" to setup the encrypted SOCKS proxy, then change location to "SSH Socks Proxy" to automatically have Mail.app, iChat, Safari and Camino use the secure proxy.
An easy way to verify the proxy is working is to add an IP Address gadget to your personal google home page:
Finally, with the Network Location module for Quicksilver, you can easily switch back and forth between the encrypted proxy.