weird firewall hits

[Johnno]

all this morning my firewall has been blocking attempted connections on seemingly every port imaginable from 5.20.161.34 which according to ARIN whois, belongs to IANA.
seems to be that most (if not all are TCP requests)
I'm behind an NAT router so not sure why this is getting passed onto my computer.......using XP home SP2, Zonealarm (latest version), avast! antivirus.
anyone got any suggestions as to whats going on?
Thanks
John

[Karl Prince]

Welcome to the world of BOGON networks http://www.completewhois.com/bogons/index.htm

Somebody (not your average script kiddy) whom has access to a high level connection to the internet (probably hacked into someone else) has "BGP announced" the ARIN network that is not meant to be routable.

Anyway, it has already gone.

It would be good if ISP's (and high level backbone providers) used the available listing services to drop these networks at the perimeter.

It would also be good if they only routed packets from their own network with source address that belong to their own network (thereby stopping many DDOS methods)

Anyway your firewall did its job, though your router seems very suspect, though do you have wireless, as it is possible it was spoofed in from there.

If it happens again, try and get a tracert whilst it is still routable, at least you then may have some idea were it came from.