Don't sweat it, sometimes sites send back that info, specially sites that are on a bigger network or have round robin capabilities or such stuff, it's just a matter of technicalities.
Don't think that every alert on your firewall is someone poking at your ports, I get over 200 alerts per day (some times more).
The advantage of Zonealarm is that you're invisible, the alert means that a port received a request and swallowed it, giving no response back.
I'm sure that there must be some way to hack it, but it's probably the safer you can be against any hacking attack other than unplugging from the net...
------------------
Phat Sites Need Phat Hosting
Get PHAT
And Now You can Get even Phatter!
TGP Hosting Special!
Sign Up Now and get 15 gigs FREE in any plan (includes TGP deal)