Hardening checklist for Suse 9.1

I'm doing a Linux installation for one of our bigger clients tomorrow, a publicly traded company. I've done quite a few Linux installs before, but am fairly new to Suse, and have never been particularly methodical about hardening the server. Does anyone have a good checklist available that I can use? This install will be a network install from the boot CD of v9.1, the server's sole purpose (at first) will be as a mail server, but it is likely that they will want it to do more down the line. We will be using postfix, there will be very few users but a very high volume of incoming mail. I plan on installing the basic web server stuff in addition to postfix. Thanks Rob