Certain people prefer the idea of leaving their computer stealthed or firewalled. And yet, as theSHAD0W has pointed out, being Firewalled/NAT-Stealthed is bad when it comes to BT. So, we have to open ports. But some of us don't wanna open ports all the time.
Others have our computers set up for DHCP, maybe for a reason, but they do. They don't set a permanent LAN I.P. address.
This is where Port-Triggering comes in. If your Router, such as the Linksys BEFSR41 supports Port Triggering, you can have the ports turned on for only as long as you use Bit-Torrent.
Here's how:
- Log on to your Router (usually through your browser, with the address 192.168.1.1, 192.168.0.1, or 192.168.2.1, etc. Check your owners manual). For Linksys Routers, this is going to be 192.168.1.1
- Type in your password, and all that jazz.
- For Linksys Routers, find the FORWARDING page. Other routers will see this as NAT -> VIRTUAL SERVER
- Linksys, click the "Port Triggering" Button you will see. Other users try to find something similar, "Application Ports/Triggers", etc., not your standard virtual server.
- On a new, blank field, enter "BitTorrent" as your application name. (This doesn't matter really, but it makes it easy to identify)
- Your Trigger Port range will be 6881-6889, if you must specify: it's TCP.
- Your incoming or private port range will be your client's range. By default, 6881-6889 or 6881-6999 should be fine.
- Click OK/APPLY/SAVE, then leave and return to the page to make sure the settings sticked.
- Log out of your router, and enjoy remaining secure while still getting full use of Bit-Torrent.
Whenever you connect to a peer in the trigger range, your router will automatically open up and forward the ports for you. Once you close Bit-Torrent, the router will close up your ports again. This will work regardless of your I.P. address.
Unless, of course... you have two computers using bit-torrent at once beneath the same router. I'll let you experiment and play with that one. (Hint, don't make the trigger/client ports the same).
EDIT: I've come to realize that some people also open up standard forwards to make sure it works. This is not necessary, you do not have to set up standard port-forwards, as the Port Triggering will take care of that for you. If you use standard Port-Forwarding, Port Triggering will not work as it should.