When I review my snort logs I see lots of entried like this:

[**] [100:1:1] spp_portscan: PORTSCAN DETECTED from XX.XX.XXX.XXX (THRESHOLD 4 connections exceeded in 2 seconds) [**]
07/10-19:06:09.285781

[**] [100:2:1] spp_portscan: portscan status from XX.XX.XXX.XXX: 2 connections across 2 hosts: TCP(2), UDP(0) [**]
07/10-19:20:43.704297

Now the problem is these scans are originating from my own IP & they seem to coincide with broswer requests, I can see them being logged as I'm surfing.

So my question is:

Is my system compromised?

If not is there a rule to stop this from being logged without leaving myself open to scans?
(I've looked high & low via google & snort.org)

My system: Mac G4, OS X 10.2.6, Snort 2.0, software firewall (IPFW) all on a glorious 56k dialup.

Any help would be appreciated.