Port Forwarding

[5614]

attached is an image of a part of my router configuration page.

 

i want to forward some ports.

filling in the form [shown below]

 

ID = 1 [default, just a way of labelling it]

Public Port - Start/End: the ports im going to open

Private port: what is this? what do i need to put in?

Port type: i know that [varies depending on what you're opening for]

Host IP address: what do i wanna put here? the router? my computer?

[Lance]

First you need a static IP address. Then you put that IP in the HOST IP box. I think the private box can be blank.

 

I did this a few months ago.

 

Go here for info on how to get a static Ip.

[5614]

but which IP? my computer's or my router's?

 

it is the internal IP of the computer that you want the port to be open to, this allows the router to send the info from that port to that IP.

 

do i need a static IP as my router always asigns me with the same one?

[Lance]

The router assigns each computer a different IP address. The problem you are experiencing is the router doesn’t know which IP to send information to. That’s why you have to assign ports to a specific IP address. If you already have a static IP address then you can just skip that step and use that IP. The routers don’t really have an address it just has the first few segments and the last segment is unique to the computer.

 

The difference between static and dynamic is if it’s static you assign the IP that the computer will use every time it starts up. Generally if it’s dynamic the router will randomly assign a different IP address to each computer. If you don’t have a static IP and you forward anyway then after you restart the router will forward to the wrong address.

 

Make sure you make all the computer for your router static so the router wont assign eh same IP as your computer.

[5614]

my computers were dynamic but the router was set up to assign the same IP to each computer every time.

 

they are now static.

 

i dont quite get the 'private port' thing, you cant leave it blank. seemingly you can only forward one port in each 'row' and you must type the same port number in 'private port' a bit confusing.... do i really need port forwarding? most programs seem to work quite well without it.

[Lance]

Well if it works fine then why do it at all? I only did it because I couldnt host games on warcraft III.

[5614]

i occasionally have some problems with msn, probably solved by port forwarding, however both computers use the data from this range of ports [msn messenger's] so can i not forward ports to a certain computer, as then the other computer wouldnt be able to use msn, right?

 

by the way lance, i do know the difference between static and dynamic IPs!

[Dave]

Why not give all your computers a static ip address? It's the easiest way around the problem as far as I can see.

[5614]

originally, they had a static IP assigned by the router [kinda a cross between static and dynamic] not they all now have a proper static IP.

 

if both computers on my network use the same program which uses the same ports, if i forward the port for say my computer, then can the other computer still access the internet with that program?

[Lance]

by the way lance' date=' i do know the difference between static and dynamic IPs![/i']

 

Alright, alright, I would think any less of you if you didnt.

 

What type of router do you have? If you go here and click on your router it should tell you exacly what should go in that box. My router settings didnt have that box.

[5614]

i have already done that, but now reading it for a second time i understand it better:

 

Pick a port you want to forward and enter that port number into the Public Port box. Enter the same exact port in the Private Port box. If you are unsure of the port range/ranges check the Ports list page or the software manufacture's homepage. Select the protocl type using the Port Type radial button. If you need both TCP and UDP' date=' create a duplicate configuration. The first configuration would have TCP selected, while the second one would have UDP selected. Enter the ip address you wish to forward these ports to in the Host IP Address box. This should be the ip address of the computer that has the software that requires port forwarding. Click the Add this Setting button. If you are forwarding mulitiple ports, pick another port and then repeat Step 5.

 

Most people will never need to use this, but I'm going to explain why they have private and public ports here. The Private/Public port entries are actually rather useful. They are their so you can direct traffic at two computers on your network. Lets say that you have computers running Ftp servers on your network. Lets call these computers computer one(192.168.2.10) and computer two(192.168.2.11). Lets also say both these ftp servers are running on port 21. Okay we setup your router to forward port 21 to computer one(192.168.2.10:21). So every external ip address request from ftp goes two computer one. How do we get to the second computer? Well the Private/Public port entries allow us to specify another outside port to connect to our internal port 21. Lets make the additional port, port 30. We would now setup a rule in the router with the Public Port set to 30 and the Private port set to 21. The ip address in that rule would be 192.168.2.11. So when you wanted to ftp to computer two you would specify port 30 in your ftp client. The router would see these requests coming in on port 30 and forward them to (192.168.2.11:21). Thus you would be able to ftp to both computers.[/quote']

 

this is what i think it means:

msn messenger needs: 1863,6901,6891-6900 (TCP) & 6901 (UDP)

so lets take one of those -- 1863.

 

now i have two computers using msn messenger and i want to forward the port, however both computers use MSN, how do i get around this?

using this private port thingy. im not 100% sure though quite what to do, how would i make port 1863 available to both computers? what do i fill in where?

[5614]

i'll re-phrase the question:

 

if i forward the ports for MSN messenger to my computer, can the other computer still use MSN messenger????

[Lance]

Look through the setings. You should be able to change what port it uses. Then you can forward each port to a different computer.

[5614]

and what about for other programs where you cant change the port used? can you not forward it? how does the router know where to send data sent to those ports?

[bloodhound]

if u have then u should enable uPnP. that will automatically make the router forward the required ports

[Lance]

Ahhhhhh! I'm not the person to answer these questions. Surly somebody knows more about port forwarding than I?

[daedelis]

Usually port forwarding is only necessary for server-type applications which listen on a particular port for incoming connections when the computer that application is on does not have a static and public IP address.

 

To use port forwarding correctly, you need to know 2 things: The port the outside computer will be sending the request on, and the port your server application will be listening on. Usually these are the same, unless you manually change your server's configuration.

 

First, you will need to set a static private IP address for your computer that will be hosting the server application. In my example, this will be 192.168.1.199. Second, you will enter the port the outside computer will be initiating the connection from into the first port field. Third, enter the port your server application will be using to listen for the incoming connection into the second field. Select the protocol if necessary. It's usually TCP.

 

I run a server for an application called ventrilo. It is a voice over internet application. In order for outside requests for connection to my server to get through to the appropriate computer on my internal home network, I have to set up port forwarding. Ventrilo server listens on for requests on port 3784. Because I have no other server applications running that require that port, I have no need to change the port my server listens on, therefore the incoming and private ports will be the same in the port forward. The result is this:

 

3784 TO 3784 - Protocol TCP - IP Address: 192.168.1.199

 

I can log on using the ventrilo client using my public IP address as the server IP address and it works perfectly. Others can log onto my server using my public IP address without ever having any other access to my computers, because the public IP address resides on the router.

 

You can NOT forward incoming port requests that are required by 2 computers using the method I just described here. I am not that technically inclined but I think that sort of process would require customized NAT settings.

[5614]

well, heres my problem:

 

i use MSN messenger and occasionally do not get messages, they just randomly dont appear! i thought that maybe they were being 'lost' inside my router, do you think that this is the case?

if it is [remembering that there are 2 and soon 3 computers on my network all using MSN messenger,] how can i overcome this problem?

 

p.s. i've tried re-installing MSN and doing all the normal things, its a problem that no one has ever seen of or heard of before and no one has any idea what it is, and that includes microsoft whom i have emailed, they came back with a load of usless suggestions which i had already done.

[Lance]

Thanks daedelis.

 

I don’t think that you would randomly miss a few if that was the problem. How do you know you’re even missing any if they just don’t appear?

[5614]

because it is a frequent problem, people will randomly say "u there still?" and im like "yeah, never left" and then they're like "well what do you think" and i dont know what they are talking about.

trust me, this happens alot, people will just not answer questions i ask, so i'll ask again, and they'll say "ive already said.... yes".

it happens almost everytime im on MSN and it gets very annoying!