Network lossage

This morning my housemate's computer ("it takes effort to turn it off") was displaying a DHCP error message. This seemed a little odd; I fired up both the desktop and the laptop (because MoO3 is important, see) to look. Tried the standard "kick the network and see if it's better" thing, and after a minute did successfully get blinky-lights on the cable modem. This was encouraging, so I tried to traceroute to MIT...and it died at NoX. Suck. Tried poking around the network a little; DNS lookups worked (this should have been a clue) and I could get across the country if I could think of anything useful in California. Called SIPB; nobody knew of anything wrong. Poked around some more and realized I could reach MIT's name servers and, in fact, the tunnel server. So I actually do have real network. And internal DHCP works, whoo.

Zephyr conversation reminded me that there's fiber work taking LCS out this morning, which explains why I can't get to my work machine, washington-street-elevated. But I'm a little mystified as to why I don't lose inside of MIT trying to get there. And, for that matter, why the external network dying (presumably RCN renumbered me and I failed to deal) took out my internal DHCP server; I'm sure I didn't restart the DHCP daemon. So, uh...