Port Forwarding - What is the benefit and for whom?

BitComet BitComet General Discussion
1

Hi Comrades,

I am unsure about whether to reconfigure my router for port forwarding–I am still a bit unclear about the benefits. I visited http://portforward.com/ to find out info and it had my router listed (Belkin g-type) and it explained how I need to change from a dynamic to a static IP address. As there are four PCs on my router, it sounded like a lot of work to reconfigure all of them, and, most importantly, I am not sure how I would benefit from having a static IP address.

I have been using dynamic for a long time and had favorable results with downloading and uploading. In fact, I even have configured my firewall for the specific UDP listening port that Bitcomet indicates.

So, is it worth the hassle of changing to Static IP and are there any downsides or upsides?

Thanks :unsure:

2

Hi,

When you are connected to a torrent, your client will receive requests for data on your listening port.

When your router receives these requests, it has to delay them until your computer confirms it wants them (rather then one of the other computers).

When you forward that port, your router will send ALL data on that port to just the one computer.

If you use bit torrent in more then one computer, then you need to assign one port for each computer.

As for a static ip address, this is how the router knows which computer is getting the data, if your ip is dynamic, then it may change when you reboot. You would then have to compare and possibly change your router settings each time you reboot (assuming you want to run a torrent).

Suspect

3

Bittorrent transfers are a process of negotiation between clients. Your client contacts mine to say it’s got piece so-and-so, does mine have any pieces yours wants?

Or my client contacts yours, OOPS, your firewall is blocking the port, can’t initiate contact with yours. Mine may have a lot that yours wants, on a fast connection, but since mine can’t contact yours, you’ll have to hope yours contacts mine before all my connection slots are filled up. Awww, too late, my slots are filled with clients I could contact.

That’s the point, and the benefit, of an open listen port. Port-forwarding is the process of opening said port through an external firewall like the one in your router.

Most routers, like your Belkin, require (for security) that a port be opened only to a particular IP address. The whole purpose of a firewall is to keep out unsolicited contacts, so we only want to let them through to computers who are expecting them and are prepared to handle them. Thus, the port + IP combination is enforced, port xxxxx is open only to IP xxx.xxx.xxx.xxx and no other.

Your machine is ready, with BitComet, to receive traffic on port xxxxx, so all is well. But, if you use all dynamic IP’s in your subnet, then your computer might or might not be at that IP address. It might have been assigned a different one, so for yours, that port is closed, and for some other unsuspecting computer that did happen to get that particular IP address assigned to it, the port open. So 1) BC won’t work properly and 2) the other computer has a security risk.

Giving your machine a static, unchanging subnet IP address resolves this issue. There is, BTW, no reason at all why your computer can’t have a static IP while all the others in your subnet continue to use dynamic IP’s. Just limit the range of your DHCP pool, and use one of the addresses no longer in that pool for your static IP. That’s less work.