Talk:Port forwarding

From Wikipedia, the free encyclopedia

Contents 1 description 2 "can't see" 3 port address translation 4 Information for Macintosh Users? 5 Keep The Articles Separate 6 free port forwarding? 7 Port Forwarding vs Pinholes 8 Article is extremely Jargon heavy

[edit] description

BLA Can someone expand this entry to give a general description of how to set up port forwards? In particular, is there software that can forward UDP (as well as TCP) ports? With a general application, what's the best way to determine the ports that need to be forwarded?

Yes, UDP can be forwarded just like TCP can. The article just says "network port", it doesn't exclude UDP. It wouldn't be wise to answer the first and the third question in the article, because Wikipedia is not a place for HOWTOs or cookbook entries that go this much beyond the main topic of the article. Well, the first answer would be borderline, but the second is way off-topic. --Joy [shallot] 21:51, 30 Dec 2004 (UTC)

The software you are talking about is found in the router. You access is through some IP (for example 10.0.0.138), you find NAPT or NAT and add an entry there. What I think is very relevant to this article though is UPnP, available in Windows XP, which enables programs to map these ports by themselves without user intervention. VodkaJazz 01:16, 13 January 2006 (UTC)

[edit] "can't see"

Hi! Can anyone confirm that the destination machine within the LAN "can't see" the sender of forwarded packets? I'm no expert, but AFAIK, in port forwarding the router only changes the destination IP so that a packet can reach a private IP -- it doesn't change the sender. That's part of the router acting as gateway. Thus, when the receiving end of the first packet responds, it sends a packet with the proper destination IP through the router acting as gateway. The latter, then, will appear as the sender of the packet, but it won't need to change the destination IP.

In other words, the machine within the LAN can clearly reach the one outside of it. It is the external machine which can't directly "see" the machine in the LAN.

I don't have much theoretical background, here, yet I can easily see the sender of a packet on my NATted, "port forwarded" machines. A router acting as gateway doesn't appear as the sender of a packet to NATted machines. Aside 21:05, Mar 21, 2005 (UTC)

Actually, it depends on how exactly the port forwarding was set up. The simplest setup is to change only the destination address (and possibly port). This works fine for connections originating from the exterior interface of the router, but does not work for connections from LAN to LAN - if A connects to router:80, which is rewritten to B, then B will reply directly to A, which is expecting a reply from the router and discards the packet. The rewriting of the source address is to fix this problem. It should only be done to packets originating from the LAN, however. DanielDeGraaf 02:30, 13 April 2006 (UTC)

[edit] port address translation

What is the difference between port forwarding and port address translation? — Omegatron 15:44, August 23, 2005 (UTC)

The latter refers to a specific use of port forwarding, on gateways that also do network address translation. Those devices do a series of forwardings of ports to various destinations in the internal network. --Joy [shallot] 01:54, 24 August 2005 (UTC)

there is no port-forwarding (except on the same host) without NAT, because otherwise the destination host wouldn't accept the packets because they're addressed to him. PT and port forwarding are the same.--Penosa22 23:01, 19 February 2007 (UTC)

I would argue that PAT and Port Forwarding should be defined to be NOT the same and that PF is defined as a special case of PAT. To facilitate understanding it is far more useful to look at PF as simply involving the translation of packets' FIXED external port numbers to FIXED internal port numbers as is done on most home-wireless routers for the purpose of setting up servers. In fact often the port numbers on the inside and outside are the same, with only the ip addresses being different, (public on the outside (WAN) and private on the inside (LAN), (this also provides an added layer of security).

Home owners with usually single ISP assigned ip addresses should look at PAT as making use of pools of port numbers on the ISP/global-(WAN) side and a pool of private address on the LAN or local side. The job of PAT in this case is to keep track of the multitude of internet connections host-1 (say) has to the global(ISP) side by assigning different ports to each of these connections, and remembering that each of those global(ISP-side) ports also (possibly) comes from a different ip address.

The job of PAT then becomes to remember to match up global(ISP-side) ip x, port y with the usually standard local(LAN) side ip and port adresses, which would usually be something like ip=192.168.0.2 (a private address) and maybe port 80 for web-surfing traffic.

Ofcourse if you only have one computer then all the above is irrelevent as you are then simply directly connected. 1812ahill 04:00, 21 July 2007 (UTC)

[edit] Information for Macintosh Users?

IF someone has some information on how to do this for macintosh users, I think it would be very helpful to add, either here or in another entry. thank you.

Port Forwarding is usually done using the router so it will be the same for windows and mac users.

[edit] Keep The Articles Separate

"Port Forwarding" should remain a separate article because people look for it. Everyone has seen "port forwarding" in a firewall, but who has even heard of "port address translation?" Even if by arcane logic "Port Forwarding" is a subset of "Port Address Translation," an encyclopedia needs to have the aritcles people seek and "Port Forwarding" is a big topic in itself. The articles could be cross referenced. —The preceding unsigned comment was added by 70.22.209.112 (talk) 03:11, 17 March 2007 (UTC).

Thats true, it would be great if both are separate and people get exactly what they search for...

[edit] free port forwarding?

are there any free programs that do it for you i cant seem to do this

YOU DO THAT ON YOUR ROUTER ! —Preceding unsigned comment added by 83.131.61.102 (talk) 12:36, 25 December 2007 (UTC)

[edit] Port Forwarding vs Pinholes

There is no mention of pinholes in this article, and no mention of port forwarding in the article on pinholes.

What the heck? Are there two parallel Wiki universes?

DrHenley (talk) 15:28, 3 March 2008 (UTC)

[edit] Article is extremely Jargon heavy

As someone not terribly blessed with computer skills, I can barely make sense of this article. a serious re-write for the layman would be greatly appreciated —Preceding unsigned comment added by 96.225.98.78 (talk) 00:28, 7 April 2008 (UTC)