[bittorrent] BT, Nats, and hackers at the door...

Olaf van der Spek olafvdspek at gmail.com
Mon May 30 05:20:50 EDT 2005

On 5/30/05, Bill Cox <bill at viasic.com> wrote:
> Hi, Olaf.
> I'm just fooling around with ideas for helping make p2p traffic more
> secure.  For example, if a large respected company like Cisco comes out
> with a popular internet phone, and all I have to do is plug it in, it's
> likely to be hard to hack.  Is it possible to get the same level of
> security with a Linux or Windows box that provides phone service, or do
> all those moms out there have to go out and buy dedicated hardware for
> each p2p service they want?

Why would hardware be harder to hack than software?
> Would it be possible to do the same thing for a p2p protocol?  For
> example, I could run a custom network monitor/filter that checks BT
> communication and make sure that it conforms to the BT spec, no matter
> what client I run.  That would make me feel much more confident in
> trying different clients.  Similar monitors/filters might allow SIP
> phone service to be more secure.

Would that guarantee the security of your p2p app?
> It would also make me feel better if I could more easily restrict access
> permissions of programs I install.  With most open-source installations,
> I compile, then su to root, and do a make-install.  Good thing most of
> us open-source guys are fairly trustworthy.  Could Linux/Windows be
> enhanced so that I could specify the restrictions of a newly installed
> package?  For example, a basic SIP phone package does not have to have
> write access to the disk, or the ability to open any port other that the
> phone service port, or the ability to contact non-phone ports in the
> internet, or the ability to run commands like top or who.  The kernel
> could restrict such access, and report attempted violations.

I think SELinux does things like this.
Additional restrictions (and kernel-level configuration) would indeed
be a good thing.
> Is anything like this already in the works?
> > > > What prevents you from replacing your NAT with a stateful firewall?
> > >
> > > I think I will.  However, installing and managing a stateful firewall
> > > requires more networking skill than the average mom has.  It'll work for
> >
> > Why would it require more skill than setting up NAT?
> It's possible that when IPv6 is well established, average mom will be
> buying a stateful router rather than a NAT, but I'm not so sure.

Why not?
You *will* need a router to connect multiple hosts to one internet line.

> Dynamic IPs and NATs are two more levels to help protect the end-user
> from hackers, and I'm concerned that ISPs will keep them in place even
> with IPv6.

I doubt dynamic IPs provide any security.
> > > me, but what about the masses?  How can they be protected if they have
> > > open p2p ports and fixed IPv6 addresses?
> >
> > What's the vulnerability of open p2p ports?
> I think all open ports are potentially dangerous, not just p2p ports.
> However, the current trend is to close off all ports of home users (with
> NATs), and to make their IPs dynamic.  I'd like to see average mom able
> to receive direct p2p calls or e-mails from the internet without having
> to configure a router, pay her ISP more money, or take any additional
> risk.  Is it possible?

The reason to close all ports by default is that most apps listen on
all interfaces by default while they should only be listening on

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