Dual WAN Connection

[KeepGood]

Router OS: Windows 2000 Server SP4

Client OS: Windows XP Pro SP2

Client: Bitcomet 0.70

Hi guys,

I've recently setup a Win2k server to serve as a router. I'm using Wingate to take advantage of two 10mb cable modem connections. I'm having bother (as you can imagine) when using torrents. This problem exists with every torrent client I tried (as the problem isnt really with the client) but sinse I use Bitcomet I thought I'd ask you guys here. :)

The router selects a connection with available bandwidth so the IP that is used can change without the users knowledge. I am finding I will download a torrent file, then when Bitcomet fires up I will get an 'unrecognised client' message or something to that effect. Basically from what I can see, alot of times when I download a torrent file, my router will use one connection, then when Bitcomet starts the download the other connection will be used and the tracker doesnt recognise my host.

With the popularity of 'Dual WAN Routers' growing, does anyone know if there are any plans to implement some functions in torrent clients/trackers to allow for multiple connections. I know that a couple of ISP's in the UK are going to be using connection teaming modems (4 connections) soon so something to deal with this problem will likely be needed in the future.

Thanks for any info you can give about this.

[kluelos]

Bittorrent is different in operation from most other common internet activity, because it involves peer-to-peer communication. This means that Joe's computer contacts yours, which is not something that normally happens with things like email or web surfing. In order to do that, Joe has to know your IP address, which you gave to the tracker when you scraped it and joined the swarm.

In order to make all this work, you need a stateful connection. Most of the activity you do is stateless, and the dual-wan notion depends on that. You send a request, you get a response, end of transaction. Send another request, that's the start of a different transaction with the state not preserved. This is much like dealing with a web server, where you have to supply your own state information with each request, which is faking a stateful connection because it really isn't.

If your IP address changes between each request, this will screw up the attempt to keep things stateful. For those one-shot transactions, it doesn't matter. For bittorrent though, it's fatal. When you scrape the tracker for the second time, it's expecting to have a current "account" based on your IP address. Your IP changed though, so now it's never heard of you and has no state information about you in its database.

Your first scrape put your IP address in its list, which it sent out to all the other peers, and some of them will be trying to contact you at that IP -- but you're no longer there. Or you're there some of the time, but not others. Or you send out a reply, but it's coming from your other IP, and the recipient doesn't know that IP so his firewall bounces it.

It would take a great deal of work to find a way around this, and I doubt anyone is willing to do it for the tiny fraction of people it would apply to. It's more likely that they will insist the dual-WAN people find a way to make it transparent -- that THEY do the work, not everybody else.