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by zekica 1764 days ago
It took me a long time to finally "get" IPv6.

But as soon as you don't try to apply IPv4 conventions to IPv6, it really clicks: - RA packets don't have default gateway - default gateway is always on fe80:: and is the actual host that sent the RA - You can configure hosts via RA not to send packets directly to other hosts with the same prefix (instead sending them through the gateway) by disabling On-Link flag - You can use RA and DHCPv6 over any link, not just Ethernet

1 comments

> default gateway is always on fe80::

In theory, we can reserve `169.254.1.1` as default gateway (and default DNS server) for IPv4, to get rid of DHCP protocol. I'm doing so in my embedded project for network connection via USB, because it makes network configuration static.

Just a heads up for anyone confused about 169.254.1.1: 169.254.0.0/16 is the link-local address block for IPv4, but link-local addressing is rarely used in IPv4. OTOH, the fe80::/10 address block on IPv6 is widely known since link-local addresses are mandated by the standard.