Let's talk about yum and p2p in Fedora
vvmarko at gmail.com
Mon Dec 27 11:58:33 UTC 2010
On Sunday 26 December 2010 22:11:17 you wrote:
> On 12/26/2010 02:40 PM, Marko Vojinovic wrote:
> > The only permanent solution to usability of p2p in general is IPv6, where
> > all addresses will be public and thus accessible from outside. And IPv6
> > would fix other protocols broken by introduction of NAT, not just p2p
> > stuff.
> Why would anyone want all internal machines public anyway ?
> Historically, we used nat for 2 purposes:
> (1) to shield inside machines
> (2) free up ipv4 (was an accidental consequence of (1)
There was a quite large thread on the CentOS list recently about this.
In a nutshell, the conclusion is that (1) is an urban legend --- NAT *does*
*not* (and moreover, *should* *not* ) shield your inside machines from outside
attacks. You still need to use the proper firewall for shielding.
The only benefit of NAT is (2), ie. artificially enlarging the scope of
available v4 IP numbers, at the price of breaking functionality. And this is
not a consequence of (1), but rather the primary reason why NAT was introduced
in the first place.
After IPv6 gets introduced, the number of available IP addresses will be more
than enough to eliminate any need for NAT, while for security you'll still use
the same firewall as you needed to do with IPv4. The net gain is that protocols
that were broken by NAT will not be broken anymore, in addition to the larger
Of course, some people will remain dense forever and keep implementing NAT
even in IPv6, with an illusion that it will improve their security. Those
people cannot be helped, unfortunately... ;-)
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