MI424-WR Rev D Can't assign same port forwarding to more than one IP Address

wick3dw3s

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May 16, 2014
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I'm using the MI424-WR Rev D, and I figured out how to do the Port Forwarding fairly easily. Me and my gf play Black Ops 2 for PC, and we BOTH need port 3074 opened since our NAT was showing moderate. After I put in mine, my NAT switched to Open like it should. However, when I go in the router and specify the same port for her IP Address, it errors out with a conflict saying the port is already opened for another application. Is there no way for me to assign the port to multiple IP Addresses? Any other router I've used in the past let the IP be the unique identifier, not the port number.

Also, I tried the DMZ Host for her address but it did not fix her NAT issue.
 
Solution
I have never heard of a consumer or SOHO router that can port forward a port to more than one IP address. There may be some Pro level routers that could do this but it would take some programming. What people usually do to get around this limitation is to either have more than 1 WAN side IP address so that ports can be forwarded on each incoming IP address separate, or (depending on the game) you may be able to change the port the game uses to another port on one of the PC's. Then you would have 2 different port numbers you could forward to 2 different PC's.
It looks like you may be able to change ports on one PC. Take a look here...
I have never heard of a consumer or SOHO router that can port forward a port to more than one IP address. There may be some Pro level routers that could do this but it would take some programming. What people usually do to get around this limitation is to either have more than 1 WAN side IP address so that ports can be forwarded on each incoming IP address separate, or (depending on the game) you may be able to change the port the game uses to another port on one of the PC's. Then you would have 2 different port numbers you could forward to 2 different PC's.
It looks like you may be able to change ports on one PC. Take a look here:
http://support.activision.com/articles/en_US/FAQ/Lag-Occurs-in-Multiplayer-Game/?l=en_US&c=Game_Title%3ACa
By the way the article above talks about turning off all your routers firewall features. I would not do that! Try the other things first to see if it solves your problem.
 
Solution
You can't assign a port to 2 different machines.

Lets pretend you are the router and I send a packet to your IP address on port 3074. Now you being much smarter than any router how would you know which of the 2 machines to give it to. Even if it was available what information could a router possible use to make a choice.

The thing you can do though is say I send to port 3074 you send that to machine 1 on port 3074. Then define another port say 3075 that when it receives traffic it sends to 3074 on machine 2. It really depends what the exact limitation is. If the limitation is that the server must listen on a particular port this solution get past that. If the requirement is the client ALWAYS sends to a particular port and it can't be change then you can't solve this problem with a single address.
 

wick3dw3s

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May 16, 2014
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Thank you for the responses. I thought I had email notification set up but apparently not.

I think in the past I was using linksys routers and just opening multiple ports on my one static IP, back before I truly understood what I was even doing. Now I have a better understand on why you can't assign the same port to multiple addresses. So thank you abailey and bill001g. Both of you were correct in my question. Sorry I couldn't make both of your answers the solution!