[ale] IPv6 Subnetting

[David Tomaschik]

I'm no networking expert, so I hope I'm missing something here.

According to RFC 4291, all interface IDs for unicast addresses will be
64 bits in length.  It's also widely believed that most residential ISPs
will hand out a /64 on a per-client basis.  Because IPv6 does not have
the concept of NAT, it seems that this forces all of the computers on
that connection to be on a single subnet.

This is rather disappointing to me, as in the past I have run 3 NAT
subnets off a single NAT router/firewall.  I've used one as my "regular"
LAN (workstations, one wifi SSID), a "guest" LAN (another SSID with a
different key for my guests) and a lab network (for testing things I'd
rather keep separate).  It seems to me that under IPv6 this addressing
scheme will be impossible unless I can convince my ISP to hand out a
/56.  (Or, I suppose, multiple /64s and have multiple (virtual)
interfaces on the router.)

Anyone network gurus care to shed some light on this?


-- 
David Tomaschik, RHCE, LPIC-1
System Administrator/Open Source Advocate
OpenPGP: 0x5DEA789B
http://systemoverlord.com
david at systemoverlord.com