e.g., I'm getting a few thousand a day of these:
[INFO] Sat Aug 22 11:43:44 2009 Blocked incoming TCP packet from 66.102.7.191:80 to xxx:47414 as ACK received but there is no active connection
[INFO] Sat Aug 22 11:43:44 2009 Blocked incoming TCP packet from 66.102.7.191:80 to xxx:15370 as ACK received but there is no active connection
[INFO] Sat Aug 22 11:43:44 2009 Blocked incoming TCP packet from 66.102.7.191:80 to xxx:63879 as ACK received but there is no active connection
[INFO] Sat Aug 22 11:43:44 2009 Blocked incoming TCP packet from 66.102.7.191:80 to xxx:7748 as ACK received but there is no active connection
Looking back I see these requests have been coming for months but have increased in frequency recently.
They come from a range of IPs which whois reports are assigned to Google:
66.102.7.10166.102.7.19174.125.15.2274.125.15.9374.125.15.10074.125.15.15774.125.19.11874.125.103.3374.125.103.9674.125.103.97etc.
So for what purpose is Google port scanning me?
UPDATE:
These are likely just delayed responses to a web page request made by your browser just before you quit your web browser.