Alternative Ports for Bittorrent on second PC

[flexy]

hi, stupid question maybe...

I have 2 PCs on a Router (WRT54G) and just forwarded ports 6881-6999 for the 1st PC so i can use BT.
Now i want to use BT also on the second PC.

I guess i wil have to set two static IPs for both machines, but i am clueless what port ranges are 'free' for the forwarding so i can use these as alternative ports for BT on the scond PC. (And will configure BT on the second PC so it uses these ports)

Are there any recomendations ?

thanks !

 

[dc5]

on some routers you can port foward to a range of ips. like 192.168.0.1 - 192.168.0.5 i am not sure if you can do that on your linksys. just curious why would you want more than 2 computers using BT anyways. one computer downloading everything should be ok.

 

[flexy]

yeah but sometimes i would use the laptop (over night), its qquiter and uses less power...thats why i need the other ports for the laptop 🙂

 

[dc5]

try to foward it to a range of ip's. that's if you have that option.

 

[flexy]

yeah...thats what i did. But my question was actually *what* range...right now i just have default range 6881-6999 on PC1 and then 7881-7999 on PC2. I wanted to avoid conflicts in case ports are occupied already. "What ports are free/available ?"

 

[scdill]

I was looking at this the other day. Don't know how accurate or complete it is. At least it's something:

http://www.chebucto.ns.ca/~rakerman/port-table.html

 

[dc5]

can't your router foward the same ports to 2 different computers? if you can do that, there shouldn't be any conflicts. by the way, if you decide to use different sets of ports for 2 different comptuers, make sure your BT client can change the ports to be fowarded. bit tornado has this option.

 

[Nothinman]

Forwarding the same port to more than one IP isn't possible, atleast not in a reliable way. When a new connection (or for every packet if they're UDP) is attempted on a forwarded port, how would it know which machine the packet should be sent to?

 

[VirtualLarry]

Originally posted by: dc5
can't your router foward the same ports to 2 different computers? if you can do that, there shouldn't be any conflicts. by the way, if you decide to use different sets of ports for 2 different comptuers, make sure your BT client can change the ports to be fowarded. bit tornado has this option.

How in the heck would you go about doing that? Remember, this is which (internal, private IP) machine to send incoming unsolicited packets directed at the (external, shared WAN IP).

I suppose that it would be possible to "echo" incoming UDP packets from a port on the WAN IP to that port on both private IPs, since UDP is connectionless, but with TCP that would be impossible.

 

[dc5]

Originally posted by: VirtualLarry

Originally posted by: dc5
can't your router foward the same ports to 2 different computers? if you can do that, there shouldn't be any conflicts. by the way, if you decide to use different sets of ports for 2 different comptuers, make sure your BT client can change the ports to be fowarded. bit tornado has this option.

How in the heck would you go about doing that? Remember, this is which (internal, private IP) machine to send incoming unsolicited packets directed at the (external, shared WAN IP).

I suppose that it would be possible to "echo" incoming UDP packets from a port on the WAN IP to that port on both private IPs, since UDP is connectionless, but with TCP that would be impossible.

i am not 100% sure because i returned my router (fr114p). when i had it i remembered it had an option to foward outside ports to a range of internal ip's inside the network. ex. port 6688 would foward to the following internal ip: 192.168.0.1 to 192.168.0.5

 

[VirtualLarry]

All at once? That's intriguing. I'm guessing that for TCP, it probably takes a dynamic port-forwarding/NAT approach, whichever private IP most recently made outbound communication on that port, would be the one that the incoming TCP packets addressed to that port on the WAN interface would be returned back to. Sort of a dynamic port-mapping scheme, with an overlapping range of internal private IPs. That could be doable.

 

[natto fire]

I use bittorrent on three different computers and have the port range set like so: 6550-6800, 6801-6999, 7000-7200. Has worked fine for me so far, this is with Linksys BEFSR41 router. Forwarding the same port to different IPs does not work. As previously mentioned the router would not efficiently know which port request goes to which IP. Basically a huge mess.

 

[MIDIman]

Sorry to bring an old discussion back up, but I was thinking about this, and can't you force software like Azureus to only use a specified port range? i.e. you could set a certain range of ports on one installation of Azureus, and on the other computer, set it to another range.

My Netgear 814 has the option to set port ranges to a specific IP, but not set a port range to a range of IPs.