Talk:Port forwarding

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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, 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)

"can't see"[edit]

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)

port address translation[edit]

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= (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)

Information for Macintosh Users?[edit]

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.

I have some information here is a program that does it for the mac -alec — Preceding unsigned comment added by (talk) 19:41, 11 August 2011 (UTC)

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

Keep The Articles Separate[edit]

"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 (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...

free port forwarding?[edit]

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 (talk) 12:36, 25 December 2007 (UTC)
I'm no expert, BUT... You do not necessarily need a dedicated router to perform NAT, although this is the most common implementation. If you have access to raw sockets (which Windows does not), you can mangle IP packets. This can be done on most Unix/Linux/GNU based OSes. If you use Ubuntu, for instance, it is possible to do NAT directly from your workstation (using netfilter/iptables in the output chain). This is generally used if you have more than one NIC and you can use policies to NAT to various addresses. You can argue that the workstation is now acting as a router, but you can also argue that a router that is using NAT is acting as a firewall, so...
If something is performing port forwarding then surely it's a router. It can be hardware or software. It can be dedicated or multi-purpose but it's still a router. It might happen to be a PC running linux or it might also have firewall features but it's still a router. DarrenW (talk) 15:30, 23 July 2010 (UTC)

Port Forwarding vs Pinholes[edit]

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)

I've added a link to the Pinhole article --Kvng (talk) 16:06, 8 May 2009 (UTC)

Article is extremely Jargon heavy[edit]

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 (talk) 00:28, 7 April 2008 (UTC)

The article is written technically because it is a technical subject. You don't complain that the article about plutonium mentions half lives, atomic mass, and isotopes because those are the correct terms. The article is fairly well linked to the terms necessary to understand the concept. Also, this is not a how to document, it is an explanation of what port forwarding is and what it's used for. (talk) 15:11, 25 September 2008 (UTC)Necoras
I have computer skills and I do find this article jargon heavy. I support reworking it. I don't believe you need to remove technical content to make an article understandable --Kvng (talk) 15:51, 8 May 2009 (UTC)

please add link to[edit]

hello everybody, We have a greate port forwarding tool that named Port Forwarding Wizard.This tool can support manually port forwarding and auto port forwarding with UPnP technology.At the same time,there is a lot of security thinking and management tools.

please add a link to our website

Powerful port forwarding tool

--Zhxjojo (talk) 07:40, 25 June 2008 (UTC) (talk) 22:31, 2 November 2008 (UTC) An Encyclopedia is suppose to explain topics to people that don't know about them. Jargon heavy things like this belong in a manual. Not an encyclopedia. -Becky (talk) 22:31, 2 November 2008 (UTC)

Bypassing NAT without network administrator's powers[edit]

Creating this section as a place for discussing the issue about to be mentioned by me in the article...
6birc (talk) 20:34, 17 July 2008 (UTC)

Virtual server[edit]

Please add the information that some routers use term Virtual server for port forwarding. This is stated in the Virtual server topic, but it may be repeated here as well. —Preceding unsigned comment added by (talk) 08:28, 25 July 2008 (UTC)

The Virtual server topic is a disambiguation page and points straight back to this article --Kvng (talk) 16:03, 8 May 2009 (UTC)

Inappropriate content within the body of the article.[edit]

This text should be in the talk page, not the article proper:

   Is this technique applicable on a PC inside the NAT-based network? State this explicitly in plain English.
   If it is not, specify alternative techniques applicable on a PC, without network administrator's powers, in order to bypass the limitations of NAT and achieve similar goals. (Such as the ability to run software that listens and responds to "IP:port" requests from outside the network. You can discuss the problem here.) 

I've removed it from the article. (talk) 15:10, 25 September 2008 (UTC)Necoras

Found a site that helps with port forwarding[edit]

found a website very helpful with port forwarding. its worth a look, and would be a good idea to add it to the page.

I have added it myself but since I don't have an account I don't know if it will stay.

If not someone may want to add it to the external links.

Thanks —Preceding unsigned comment added by (talk) 03:38, 3 October 2008 (UTC)

Links and references[edit]

These two websites that are being pushed are not notable and aren't recognized authorities on computing. Lets get some proper references in there. E_dog95' Hi ' 18:03, 11 October 2008 (UTC)[edit]

I suggest a link to be added to the page, because it's dedicated entirely to helping end users port forward their routers. They have a (quite large) list of commercial home router brands and offer instructions for how port forwarding is done on each. There is also a lot of information regarding explaining how port forwarding works on the site. is a clusterf--- of advertising. I propose removing this reference --Kvng (talk) 16:01, 8 May 2009 (UTC)

<"This solution is nothing but "Port Forwarding">[edit]

That comment should be moved to the discussion page. Dandv (talk) 00:10, 5 May 2009 (UTC)

PC Magazine definition[edit]

The referenced definition appears to be describing a Firewall pinhole not Port forwarding or Port mapping. I don't disagree that Port forwarding and Port mapping are synonymous but don't find the reference on-point and I think should find a better reference --Kvng (talk) 16:15, 8 May 2009 (UTC)

example section needs fixing up[edit]

The example section doesn't even pass a basic grammar test. Rtdrury (talk) 21:58, 14 May 2009 (UTC)

Is it safe?[edit]

The following was added and removed anonymously to/frem the article. It may be useful information but in this form it is not ready for inclusion --Kvng (talk) 15:52, 28 August 2009 (UTC)

Port Forwarding opens ports on your computer that if are not being used by a program Example: Skype uses port 8080 forward this port when Skype is installed if you forward it without Skype installed then you are vulnerable to an attack. So in essence Port Forwarding is safe to a certain degree.

Tom's FAQ

Q: I use no programs but windows mandatory keeps my ports open using my router is it safe?

A: It is best to turn off all unused ports so that no hackers may get through.

Q: How many ports is there?

A: you shouldn't have to use any ports other than 1 - 9999 (except proxy ports of course).

Q: If i Port Forward will other people on my network be affected?

A: if you leave the IP box blank yes. but if you type your IP in example: 192.168.107 then no it will affect your IP only.

Q: Can hackers get through used ports?

A: No. which is why i say make sure the ports you Port Forward are being used.

Reflective port forwarding[edit]

Reflective/Hairpin Port Forwarding[edit]

There doesn't seem to be any information on this article on reflective (aka hairpin or outbound) port forwarding [1] whereby traffic from internal clients to external port addresses are also forwarded. DarrenW (talk) 15:20, 23 July 2010 (UTC)

UDP relay[edit]

I'm under the impression that UDP relay and port relay are synonyms for port forwarding. These terms do not come up in a Wikipedia search but they do come up in an internet search. I'd be happy to create some redirects if this is so. --Kvng (talk) 00:42, 2 March 2011 (UTC)

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  1. ^,5