How secure is port forwarding?

[pgwerner]

I frequently download files over several peer-to-peer networks, however, I'm connected to the net through DSL and have my computer behind a router-based firewall. I would like to share files of my own rather than just "freeload" off the p2p networks, but there's no way I'm going to consider disabling my firewall just to open up a shared folder to others. (I'm frankly more than a little dismayed by some of the casual "disable your firewall" type of advice I hear in p2p circles - firewalls are there for a reason; there are just too many malicious jerks out there on the net to justify having a broadband connection with the proverbial door left wide open.)

I've heard that I can use a technique called "port forwarding" to designate a shared directory that is unblocked by the firewall. Is this really a safe technique, or can hackers easily break out of the shared directory into parts of my computer where I don't want visitors?

BTW, if this makes a difference, my computer is a Mac OSX 10.3.4-based system and Limewire is the main application I use for p2p, though I also have Virtual PC running Windows XP and sometimes run Shareaza and KazaaLite on it.

Peter

[Malakai1911]

Port forwarding has nothing to do with file sharing per-se, and does not determine whether or not malicious users can break out of a shared directory.

Forwarding a port allows ingress to a server (in this case, whatever P2P or FTP Server you might want to run), the router (only router's do "forwarding") just hands off incoming TCP/UDP packets to your computer behind the router. If there were not services running on said port, then those packets would be denied.

Anyway, it would come down to blind faith as to whether or not you think your p2p software would keep a user locked into a directory. I feel just fine sharing on eMule,

[ducttapeBigSexy]

If you're really worried about a p2p app sharing more then you specified, stick to open source ones (Limewire is) - major security flaws like that would be discovered pretty quick, and no one would pretty much ever use it (i.e. ES5 :) )