Private Networks

I hope this is the right place for my query. I recently started getting a window displayed every time I connected to the internet or disconnected from the internet. The message was generated by the CFW and reads “New Private Network Detected” “The Firewall has detected a new private network that your PC is about to join. You may either close this window or follow the steps shown on the screen”. These are to give a name to the network and then indicate if I want to trust the other PCs on the network. I have absolutely no knowledge of this and am worried about what it is trying to do.
My question is: Is there any way of determining where this originates, as the FW gives absolutely no clue about its origins. I have an ADSL connection to the internet and only use a line connection, no radio.

Hi Ghost Rider, welcome to the forums.

What happens here, depends on your ISP & how things work at their end. Since I don’t know yours, I’ll give you mine as a example & see if the same holds true for you.

I’m on HSDPA dial-up. My ISP hides me behind what is often called a transparent proxy. When I connect I see my IP address as being 10.x.x.x. Obviously, I’m on some sort of internal network of the ISP, since 10.x.x.x is a private IP, not an Internet IP. Also, the IP is dynamic & changes every connection. Now, if I didn’t do something CFP would detect every unique 10.x.x.x that I’m issued with as being a new Network detection. In order to avoid this, I created a My Network Zone, imaginatively called ISPDUN, & defined it as - For good measure, I block any incoming packets from ISPDUN… but, there doesn’t appear to be any for this ISP (they must be blocking them at their end, usually there are loads).

What about unchecking:

Would that work?

I get a lot of ICMP type communications from some server of my ISP. Currently I blocked that communication, but sometimes I wonder if the connection will be faster if I don’t block those.

Yes it would stop the messages, but it would also stop CFP from detecting any new networks (obviously) & stop CFP from treating the existing network (the one causing the prompts) for what it is (probably not a true Private Network).

ICMP: Which type of ICMPs are they?

I must be getting at least a hundred in a day of these. It’s always the same source machine, and I believe the machine belongs to my ISP servers:
Blocked by Windows Operating System, ICMP, Source Port: Type (3), Destination Port: Code (13)

So far I had been ogling at the log, just now I googled that ICMP code. I realize it’s because NETBIOS is blocked across the router. And for some reason (we discussed this before in a different thread) the way things work on this machine is if reverse name resolution fails on port 53, it tries to connect to UDP port 137. This won’t go through the modem because NETBIOS is under BLOCKED PROTOCOLS.