You can turn that off by opening SecurityCenter, then PC and Home Network Defense, and select the router or modem and click Edit and then set it to 'Don't Trust Network'. Nothing can connect anyway without permission assuming everything is passworded in the network, i.e. the router or modem is using secure mode.
You can also turn off the Alerts in SecurityCenter > Navigation > General Settings and Alerts > Informational Alerts.
The issue that you are having right now is a simple one and it can be fixed easily. Kindly Check the IP address of the devices which are marked as intruders. And then get into firewall settings and add those IP addresses and save it. Once this is done those devices will not be marked as intruders.
Gopinath - I don't want to allow them in, but don't want it to report on what I assume is something like a simple ping. I don't want anything shared out from this machine and turned off all sharing, but there must be some way to turn off alerts for what obviously are not actual intrusions. I mean, the IP phones clearly aren't accessing anything in this machine.
Ex_Brit : Will setting that network to untrusted in any way disrupt current abilities when it comes to HTTP, FTP, etc. for normal use? It sounds like this could be a good solution.
It shouldn't but give it a try...and there's the other alert setting I mentioned anyway.