# Port Forwarding Problem - Linksys WRT120N



## avrus96 (Jul 10, 2009)

Hello TSF,

I have a problem with my Linksys WRT120N router; I am unable to verify any open ports through port-checker websites, yet command prompt verifies my static IP, and I have correctly set the port range forwarding in the router's web config page.

More details:
-I've set the static IP to one lower than 192.168.1.100 to avoid DHCP conflicts
-I used to own a WRT54G with no such port-forwarding problems
-uTorrent ports always clear as open, but I now realize that this is simply successful UPnP port forwarding; e.g. when uTorrent sets its random port to 42362, a website which checks ports would confirm that port 42362 is open, but all other ports remain closed due to "Connection refused" or something to that effect
-I've tried using Google's public DNS servers (8.8.8.8, 8.8.4.4) but that didn't change anything
-I've turned off Windows Firewall to the best of my knowledge, and have disabled the firewall settings in my router configuration
-I've tried setting up my IP as the destination of a DMZ through the router setup, yet I still have no open ports
-The main reason for trying to open them is to generally improve online gaming connectivity (I used to need it for hosting BF1942 servers, but now it's mostly for convenience)
-I have no Norton/McAfee/Symantec antivirus installed and no 3rd party firewalls installed
-I'm running Windows 7 Pro x64, but the situation hasn't changed since I switched from Windows Vista Pro x86

Anyway this is all the relevant info I could think of.

Thanks in advance for the help - and for the previous support you've given me.


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## 2xg (Aug 5, 2009)

Hello,

Is this your main concern?


> -uTorrent ports always clear as open, but I now realize that this is simply successful UPnP port forwarding; e.g. when uTorrent sets its random port to 42362,


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## avrus96 (Jul 10, 2009)

No, my main concern is forwarding other ports and the fact that even with a DMZ set up, no port-checker tool reports that they're open (I was using canyouseeme.org).
I don't really care about uTorrent; I just wanted to mention that as the only case where ports did show up as 'forwarded' in my system.


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## af3 (Jun 18, 2008)

Perhaps the ports are opened, but the test fails because the game server is not listening on those ports? (The door is opened but nobody's home?)


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## avrus96 (Jul 10, 2009)

Hmm.. that's an insightful way of looking at it. I suppose this would at least better explain uTorrent's ports only showing up as 'open' when the program was configured to them.
It's just that I'm sure that all of my forwarded ports used to show up "open" when testing them with the WRT54G. I suppose that since I have no immediate need for forwarded ports, this explanation should be fine.

Thanks.


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## af3 (Jun 18, 2008)

Yeah, as far as I know there is no reason for them to appear open unless a service is actively listening and sending acknowledgments to the incoming requests.



> What is port scanning? It is similar to a thief going through your neighborhood and checking every door and window on each house to see which ones are open and which ones are locked.
> ---snip---
> Port scanning software, in its most basic state, simply sends out a request to connect to the target computer on each port sequentially and makes a note of which ports responded or seem open to more in-depth probing.


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## avrus96 (Jul 10, 2009)

Ok, I downloaded portforward.com's port checker tool and all of the ports on my DMZ'd machine are definitely open. - Guess I should probably close some, lol. :3-smash:

Thanks a ton, man!


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## af3 (Jun 18, 2008)

Yeah, lock down your software firewall!

It seems I was mistaken!



> A SYN scan will tell the port scanner which ports are listening and which are not depending on the type of response generated. A FIN scan will generate a response from closed ports- but ports that are open and listening will not send a response, so the port scanner will be able to determine which ports are open and which are not.


It's possible that the TCP stack will respond and say "closed"!


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