natd vs G4 and wireless crowding
 

2 issues: Wireless does not share well among disparate networks. If you are in an area where there may be other wireless signals (apartments, dorms, etc.) then your airport may be getting crowded out by other wireless signals, including mocrowave ovens, 2.4GHz cordless phones, some flourescent lights, and many baby monitors.

Grab iStumbler to get an idea of what signals are prevalent in your area. If you are trying to troubleshoot network configuration on a flaky wireless connection you will go insane.

Second point. natd is not flaky, and is to be revered for what it does. There are many things that can go wrong because it is inherently cheating the system. Also, for safety, it runs in userspace, while the rest of the network runs in kernel space. And bitTorrent is totally cruel to nat devices. I switched from using a linksys router to natd on my mac because bitTorrent was killing the linksys router.

(TECHNICAL STUFF:) natd being in userspace means that all data going through it must get COPIED from kernel space to userspace, get mangled by natd, and COPIED again from userspace to kernel space. Leaving and coming back. The reasons are technical, and the problem is that this copy utilizes memory bus, something that happens to be in really short supply on the last model G4s. The CPU is fast, 1.5GHz or so, but memory is slow, 133-166 MHz. And it's 32 bit. The G5 introduced 64 bit 1GHz memory busses, and have gotten faster. The Intels are using ~800MHz 64 bit. natd is cruel to the G4 memory bus.

It shouldn't run away, it should be fine. Mine runs for weeks or months with no problem, but does eat CPU under network load. But if you really want NAT that runs fast on that architecture, then Sustainable Softworks has a kernel based NAT and really nice, trustworthy software. If you are interested in learning about networks, this is a good step. It's $100 shareware last time I checked. Worth every penny for learning, understanding, troubleshooting, and controlling IP.

That nat problem is harder, and is less likely the problem. Eliminate the wireless portion of your network before you assume that the problem is anywhere else.

-ED.