More bad traffic in past 2 weeks

[christoph at linuxsoup.com]

I'm starting to see more & more denied packets 

Denied packets from cpe-68-112-252-121.ma.charter.com (68.112.252.121).
  Port 65535	(igmp,eth0,input): 1 packet(s).
Total of 1 packet(s).

behind my Linksys Cable/Router.  At first, it appeared to all come
from a single server, but todays log has 24 servers logging denied
packets.

Anyone aware of what might be going on?  I have not looked at it in depth.
My linksys is setup default with no DMZ and no forwarded ports.

-christoph