RE: [PCTECH] Need firewall protection,

[oliver.wenzel@xxxxxxxxxxxxxxxxxxxxxxx]

Hi,


>It is that last part I'm unclear on.  Also fuzzy is the part where I have
>more than one PC communicating on the internet simultaneously through 
this
>router; how does the router know which PC to route the legit traffic to?

Your router makes an adress translation. Your machine PC-A sends a TCP/IP 
message
from port 2235 to port 80 of target. So the router now has a table :

        PC-A  2235  80  TARGET  ROUTER 1234 80 TARGET

Basically, your connection from PC-A runs through port 1234 on the router. 
If your
PC-B would contact the same target, the router would assign port 1235.
If target replies to port 1234, PC-A will get the answer, on port 1235 
PC-B would get
it.

To prevent software from dialling home, you can close all unnecessary 
outgoing ports on the 
router. Only open the ports you need. This will not prevent tricky 
software to phone home through
ports like http (80), as you need to allow this port to be able to visit 
the www.

Regards,

Oliver