Re: Scaling Max IP address limitation

From: David Stevens
Date: Sun Jun 24 2007 - 15:55:12 EST


> <Unrelated wishful thinking>
> I keep having hopeful dreams that one day netfilter will grow support
> for cross-protocol NAT (IE: NAT a TCPv4 connection over TCPv6 to the
> IPv6-only local web server, or vice versa). It would seem that would
> require a merged "xtables" program.

You don't actually need it (at least for easy cases like that),
because IPv6 defines IPv4 mapped IPv6 addresses of the form
::ffff:a.b.c.d. These will generate IPv4 packets for a.b.c.d, from
a v6 socket.
Unless you're using v6only binding (a sysctl option), you can
connect to v6-only servers using a v4 network and a v4 address of the
server. The peer address on those connections will show up as a v4
mapped address, and all the traffic will be v4, but the socket layer
is all v6.

+-DLS


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