Hardware Firewall/ Port Forwarding Help

[d4no]

Ok i'm using this program where you can connect to other people though other IP and a Port. I was using it as an experiment. BTW it's a Linksys BEFSR41 Router or something like that.

Step 1

I had DMZ enabled. Other person connected to me thought same port. Everything worked fine. Messages went through fine and everything.(expected this)

Step 2.

DMZ disabled no ports forwarded. Same thing everything worked fine.

Step 3

DMZ Disabled ports forwarded. Same As above(expected this)

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What I don't get is why it still works with no ports forwarded and DMZ off. Shouldn't the firewall be stopping access to that port. Or does it just restrict it or what? Because using emule as a reference, when I have ports forwarded or DMZ on i get a it says it's receiving files. But with no DMZ and no forwarded ports I get a red X and says it can't connect . Meaning I'm behind a firewall and whatnot. Whats wrong? Is this how it's supposed to be?

Another thing. When I connect to port 7557 on the other persons computer. netstat tells me that I'm sending through port 3214. But when I scan both ports 7557 and 3214 and it says they are closed. And yet I can still send and recieve messages. How does that work?

 

[JackMDS]

Welcome to AT Network Forum.

Specific Ports needs to be open only if the Outside Signal comes first to a passive computer.

When an application works from your system out it might use other ports and be ready to receive info back to yet other ports, the firewall is smart enough to take this into consideration.

Since you keep the name of the application that you are using as a ?Secret? I can not tell you more.

:sun:

 

[d4no]

Well it's not sepcific program. I'm just doing some experiements so I can learn what's going on.

So basically if I initiate the connection the ports can be closed and still revieve information?

 

[JackMDS]

Yeah Cable/DSL Router works this way.

Software Firewall can also be set to block both ways.

More here:http://www.ezlan.net/routers1.html

http://www.ezlan.net/myip.html

http://www.ezlan.net/serving.html

:sun: