Default attitude to intrusion attempts


Could someone please clarify what might be going in the following scenario.

Without any tweaking of the settings following installation of the Comodo firewall (V4), after several hours online no intrusion attempts get blocked.

If I then select “block all incoming traffic” via the stealth wizard I have several intrusions blocked as time passes. My assumption was that the firewall’s default was the stealth position, but the latter would suggest otherwise. It seems that the firewall was permitting these intrusions when in default mode, so what could they be, given that the firewall doesn’t perceive them as a threat?

The application is usually windows operating system, protocol UDP, the source IP is usually (which I’m sure is my router) with destination most commonly (which I think is my laptop – can’t get ipconfig to stay on screen long enough to read it) or

If I set the firewall to “alert me to incoming connections” then block the request, the application appears as windows\system32\svchost.exe

They seem to come in waves; two or three hits at the same time. My imagination has provided answers with notions of simple but pointless wireless communications between my laptop and the router for some reason, but I really haven’t a clue.

I can set rules to allow these in if necessary, simply to keep the log free of clutter, or is there an easy way of resetting the firewall to default, without reinstalling. Many thanks in anticipation