How can p2p work if you do have no ports listening?

Ulysses_ · 10-18-2010, 07:11 PM

In emule p2p filesharing there's this thing called the id that is low if you do not configure your router for certain ports to be listening for incoming connections, forwarded by the router to ports on your pc. When the id is low, your downloads take longer or something like that.

But if you have no listening port, how can a peer download from you?

neonsignal · 10-18-2010, 08:07 PM

Quote:

Originally Posted by Ulysses_

But if you have no listening port, how can a peer download from you?

If you are not port forwarding, then other peers can only download from you when your client initiates the connection (which it does). This can only happen if the other end is accepting incoming connections. Two peers that are behind NAT or filewall cannot talk to each other, which reduces the effectiveness of the system.

There are other ways to get around this issue (eg VOIP using STUN servers), but that requires a public mediator, whereas peer-to-peer networks are aiming to be decentralized.

Ulysses_ · 10-18-2010, 08:16 PM

How about making all people with a listening port public mediators for the rest of us?