File this one under requiem for a geek and complexity crash.
Sometime around I updated our MacBook to 10.5.7 it developed a WiFi connection stutter. It would connect to the family network, pause, disconnect, and reconnect. On the second reconnect it would ask for the network password even as it took the correct password from the keychain and displayed it inline (so if one hit return it would connect).
Before the update, about 3-4 months ago I experienced some odd XP networking issues, sometimes including messages that there was an IP address conflict 10.0.1.5 - yet that address did not seem to be in use. I was seeing other problems at the same time, so I set hat aside.
Today, when walking new our Airport Express, I noticed our iPhone-converted-to-iTouch was only showing 2 bars in its network display. It clearly wasn't connecting via the closest WDS station.
With that last clue I decided to inspect our older-device 802.11 b/g Airport WiFi WDS network.
After installing the latest Airport Utility update I discovered that while our Airport Express light was green it was not, in fact, authenticated on the network. It was in a twilight state. At some level it was connected, but at another level it was not.
That could explain the MacBook stutter, since the MacBook is often moves between the Extreme and Express domains and could connect to either one.
Power cycling the Express alone didn't fix it, so I moved it next to the Airport Extreme. This time it did show up. I tweaked some settings, including auto-setting the clock to time.apple.com (I thought this used to be set, but was turned off on both my devices when I inspected them. Is it new?)
That's when I saw the Express was assigned 10.0.1.5, which may explain the odd XP address conflict message and networking issues.
Now the MacBook WiFi network address stutter appears to be gone.
Simplify is one of my post complexity-crash themes. There's too much emergence in the modern computational world, and too many ill-defined membranes.