Re: IPv4 v IPv6
Hi.
On Tue, Jun 18, 2019 at 09:56:17PM +1200, Richard Hector wrote:
> On 18/06/19 3:38 AM, Reco wrote:
> > Hi.
> >
> > On Mon, Jun 17, 2019 at 10:38:27AM -0400, Gene Heskett wrote:
> >> But that opens yet another container of worms. If I arbitrarily assign
> >> ipv6 local addresses, and later, ipv6 shows up at my side of the router,
> >> what if I have an address clash with someone on a satellite circuit in
> >> Ulan Bator. How is that resolved, by unroutable address blocks such as
> >> 192.168.xx.xx is now?
> >
> > More or less yes. It's called ULA (Unique Local Address) in IPv6 lingua.
> > If you're using anything from fd00:/8 - you're safe.
>
> As long as you choose them randomly. If you decide to use fd00::/64, or
> something else predictable, you may run into conflicts ... but only if
> you connect directly to their network.
No sensibly configured router will allow forwarding ULAs to the
internet. A scenario you're describing is therefore impossible unless
one adds NAT66 or some kind of VPN to it. In the former case
predictability of site addresses do not matter, in the latter it's
solvable with the appropriate amount of custom routes.
> Better safe than sorry though.
As long as it works for you - sure.
> The main reason I'm using v6 is that 2 networks I'm running a VPN
> between both chose 192.168.1.0/24, and I can't change either ...
So? If your VPN is running in L3 mode it's still possible to add some
kludges to IPv4 routing. If your VPN passes L2 - you're doing it
terribly wrong.
> There are online random ULA generators - but I'm not convinced one of
> them didn't give me the same block twice, or whether it was my own error.
Never used one. IPv6 /8 block consists of 2^56 unique /64 subnets.
Surely it's possible to choose several unique /64 subnets by using, say,
ipv6calc.
Reco
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