UDP Port Scans

[m0ng0d]

The part the screenshot doesn’t show are the Ports that the rule is specific for… basically it is my rule that enables Bittorrent downloads.

Rule D in my “How To”

@m0ng0d post:1

Rule D
Now sometimes a response to our communication request is going to come in on a diferent port. Take Bittorrent for example, we request a file and the download starts on a predetermined/configured TCP/UDP port, i.e. 6881 by default. For each file we want to download simultaneously, we need a new TCP/UDP port, i.e. to download 4 we would need 4 ports… 6881, 6882, 6883, & 6884. Similar to opening the ports on our Firewalls/Routers (without the need for forwarding, as the communication is already comming into our PC).

I want to… Allow requests for incoming TCP/UDP communication (on ports 6881, 6882, 6883, & 6884) from any PC on the web to my PC

Using the Rule building blocks: (just as with Rule B, we could select to Add a new Rule and move it above Rule A, or you could right-click Rule A… Add Rule… Add Before [either way works])
Action: Allow (we want to make a rule to let requests be made)
Protocol/Direction: TCP/UDP In (Even though we asked to dowload a file [feels outbound], the response is coming back on a different port than our request; therefore, it is going to look like the remote PC is trying to request in inbound communication)
Source IP: Any (Let the request come from anywhere… somewhere on the web in this case)
Remote IP: Zone: [LAN] (remember, InBound Rules will always have a Remote of our PC [whether we specifically set its IP address, its subnet / Zone, or use Any])
Source Port: Any (we don’t care what port it left the remote PC on in this case)
Remote Port: A set of ports [6881,6882,6883,6884] (we only want to allow the remote PC to sent to the ports we configured Bittorrent to use)