this tid bit of my firewall log may interst u
not all traffic is logged-only that which doesnt match the rules
i dont understand this as well you -but i do tend to think its traffic i havent asked for
im only surfing the bloody net -checking emails and stuff
and this continual pecking at my firewall comes in waves ,similar to how u describe
it does seem co-ordinated(just dropped anICMPping from them as i type)
i live in Australia and it mostly comes from servers within oz ,however sometimes
.TW ,
.RU ,
even (you'll like this)devnull.someone.some*****ingdomain.com
( * added so i didnt swear ok? )

1st time i saw that i just disconnected-had it a few times since-just dropped the packets
most of them come from commindinco server's -who run or own quite a few large servers in this country(just dropped another 2 pings from .TW)
it happens all the time,its driving me mad and i want to get to the bottom of it
it was the motivation to join AO
anyway have a look if u got the time