network monitor blocking all web traffic after windows update

I’ve been using Comodo Firewall in pretty much its default state for 9 or 12 months now. Starting a couple of days ago I couldn’t access anything through my web browser, email, or even ping my isp. Possibly coincidentally windows update ran at just about the time this problem started occurring. I eventually started digging around in the firewall settings and have isolated this rule, which appears to be the source of the problem:

BLOCK AND LOG IP In or OUT from IP [ANY] To IP [ANY] Where IPProto is ANY

As far as I know this is a default rule, and things were working before just fine. I’ve now added the following rule just above the blocking one:

ALLOW IP OUT from ZONE [my network adaptor] - To IP [ANY] Where IPPROTO is ANY

and that seems to have solved my problem for the moment.

I’m now working my way through some of the FAQ’s to understand more about what is going on and why, but my immediate concern is why all network traffic would have stopped working, if the problem rule really is a default, and if I have opened up an unnesesarilly broad range of things with my new rule.

Thanks for any insight or assistance.