There is a chance that they have some automatic DDOS protection mechanism kick in, I know they have some pretty aggressive counter measures in place to protect their links.

Anyway, the server is definitely 'open to all takers', nothing there that could cause this. Also, last Saturday ABN-AMRO (one of the bigger Dutch commercial banks) went offline for many hours due to a huge DDOS, this may be related but I never thought my lonely blog would be in the line of fire.