Forwarding the same ports to two computers on a LAN

[PanzeR_1987]

Hi guys

I have two machines setup at home connected to one router.

At the same time me and my fiance play online games, but one particular game i require to forward the ports on my router.

I am able to forward the required ports for PC 1's ip address, but when port forwarding the same set of ports to PC 2's ip address the router gets a conflict saying "ports already specified on PC 1's ip address"

What i was thinking was that if i get another router, connect PC 1 to the first router then connect PC 2 to the other router (disable dhcp and assign a different ip address to the second router) then bridge both routers together using a crossover cable.

Is this at all possible if i get the settings right? could the 1st router forward ports (for example) 1,2,3 to PC 1 and the other router forward the same ports to PC 2?

Thanks for your help

 

[llwyd]

What router is it? surely you can forward the port for all clients

 

[k4p84]

What router is it? surely you can forward the port for all clients

exactly what i have done and i have two other housemates playing cod 4 and 5 at the same time as me, no issues................ well other than having a crap isp, SKY.

Ed

 

[PanzeR_1987]

its a Siemans gigset 587 dsl wireless/wired router

 

[PanzeR_1987]

ah excellent! will find another cheap router then!

cheers guys!

 

[Youngie1337]

What router is it? surely you can forward the port for all clients

Indeed you should be able to. Without having the thing in front of me I can't work lol! Maybe see about updating the firmware on your router?

 

[PanzeR_1987]

firmware is up to date, checked the tiscali site erlier

 

[JN]

Almost all routers will let you 'open' ports so that data on that port is allowed to pass through the firewall, but I've never heard of port forwarding to more than one IP.

For example if you are running a web server behind your router on an internal IP (say 192.168.1.1) and you want to add another web server (192.168.1.2) I dont think it would be possible to tell the router to forward requests coming in on port 80 to both of these IP's as it wouldn't know what requests were intended for what server.

Maybe if you was a Cisco boff yu'd be able to write some kind of filtering depending on headers in the packets, but for the average router I don't think its possible.

Correct me if i'm wrong tho..

 

[Youngie1337]

Almost all routers will let you 'open' ports so that data on that port is allowed to pass through the firewall, but I've never heard of port forwarding to more than one IP.

For example if you are running a web server behind your router on an internal IP (say 192.168.1.1) and you want to add another web server (192.168.1.2) I dont think it would be possible to tell the router to forward requests coming in on port 80 to both of these IP's as it wouldn't know what requests were intended for what server.

Maybe if you was a Cisco boff yu'd be able to write some kind of filtering depending on headers in the packets, but for the average router I don't think its possible.

Correct me if i'm wrong tho..

Indeed, you can always contact the routers makers for some information, they normally will give you additions to their firmware. I got some from Linksys who helped me for my LAN sessions . You can always get unofficial firmware which has added new features.

 

[Rastalovich]

Almost all routers will let you 'open' ports so that data on that port is allowed to pass through the firewall, but I've never heard of port forwarding to more than one IP.

I`ve never seen a standard shipped router have the option to do it either.

I'd assume that if any1 has done something like this, it'd be more than likely on a linux-firmware upgraded router.

I'm sure u could do it on a pc, using a pc as a router. I mean this is how some laptop (not necessarily legitimate) software can be used to introduce itself as the same receiver for port information as the pc it's intended to spy on.

 

[JN]

I`ve never seen a standard shipped router have the option to do it either.

I'd assume that if any1 has done something like this, it'd be more than likely on a linux-firmware upgraded router.

I'm sure u could do it on a pc, using a pc as a router. I mean this is how some laptop (not necessarily legitimate) software can be used to introduce itself as the same receiver for port information as the pc it's intended to spy on.

Yeah agreed. It's 'do-able' if you simply want to sniff a port and receive the same data that the specified port it, but for two machines to receive data intended for that machine only is going to take some serious sorting by the router/firewall and then only on some kind of custom/enterprise firmware.

 

[llwyd]

Port sniffing = naughty naughty. Thats how _someone_ got the password for the wireless in work

 

[Youngie1337]

Port sniffing = naughty naughty. Thats how _someone_ got the password for the wireless in work

was that packet or port sniffing? Port sniffing generally means sniffing for a Pong from the Ping to see for open ports. Don't get me wrong, information can be intercepted from ports. Mine are all stealth.

https://www.grc.com/x/ne.dll?bh0bkyd2

 

[Rastalovich]

Think u'll be a bit screwed if u want the 2 pcs to talk back to the sender too mind. I mean it's possible if the receiver is geared up to distinguish within the info which of the 2 pcs is talking to it.

 

[Toxteth O'Grady]

In the game's multi-player config file on each client pc you should be able to set the port it uses. Sofor example if the game's default port is UDP 20800, leave it at that on PC 1 and change it to 20801 on PC 2. You should then be able to set up forwarding rules in your router to each unique pair of IP/UDP numbers.



TOG