On 2023-04-18 11:04, Nohk Two wrote:
BTW, I run pfSense
for my firewall/router and it supports multiple /64s. If my
modem was in gateway mode, I'd only get a single /64.
I have a question regards to the amount of the IPv6 addresses one
can get from his ISP.
For my case, my router use PPPoE to get the IPv6 from the ISP. The
router got an IPv6 prefix for the router. The router also issued
the DHCP-PD to the ISP to get another IPv6 prefix.
The first IPv6 prefix is for the router itself and the second IPv6
prefix is used to configure router's LAN devices either by the
SLAAC and/or RDNSS and/or DHCPv6...
My question is that is it correct that, for the first IPv6 prefix,
the router could get 2^64
(or 2^72
in your case) IPv6 addresses since the ISP assigned the IPv6
prefix to the router ?
Of course, router has no reason to assign so many addresses on
itself. Router usually assign one IPv6 address which the interface
id is based on the MAC address.
Actually, it's a bit different. First off, the link local address
is used for routing. This address starts with fe80 and every IPv6
capable device has one. Second, while my router has a single IPv6
address, it's prefix is a /128. This means it can't communicate
directly with anything. All traffic for that address has to be
routed via the link local address.
In fact, you don't even need a global address on the WAN port. If
you had to reach it from elsewhere, you could use any other global
address in it, such as the LAN address. It makes no difference, as
any address on the router has to be reached over the link local
address.