Re: AT&T UVERSE Native IPv6, a HOWTO

[Owen DeLong <owen () delong com>]

On Dec 2, 2013, at 18:05 , Ricky Beam <jfbeam () gmail com> wrote:

> On Mon, 02 Dec 2013 20:18:08 -0500, Owen DeLong <owen () delong com> wrote:
> > You don't, but it's easy enough for Windows to do discovery and/or negotiation for firewall holes with multicast and 
> > avoid making
> ...
>
> Actually, your process still makes a very dangerous assumption... you have to assume the address passed via multicast 
> is, in fact, a local address.  Since it is necessarily outside your prefix, you have to either make assumptions about 
> what is "close" to your prefix -- assumes the site is contiguous, or trust any address passed to you.  Hackers will 
> have fun screwing up your firewall rules and potentially breaking into your servers. (if you're foolish enough to not 
> have any other layers in your network, which is likely with home networks.)

Not really... First of all, domain or other windows authentication could be used to validate the request.

Second, if it's site-scope multicast, unless both your ISP _AND_ your own router are doing something wrong, it 
shouldn't get forwarded into your site from outside.

> > ... They can't get away with flat out saying no...
>
> Says who? TWC has been saying "no" for years. (unless I'm mistaken, "always".)

No, they've said "get a business connection." Close to "no", but not identical.

Owen