simple DHCPv6 config with /56-Prefix

Simon dhcp1 at thehobsons.co.uk
Mon Aug 22 18:34:57 UTC 2022


Adam Nielsen <a.nielsen at shikadi.net> wrote:

>> This is not true in the IPv6 world. All it needs is for a router to
>> advertise that both prefixes are on-link and the hosts can
>> communicate directly. This is one area where IPv6 is fundamentally
>> different (better) than IPv4. For completeness, a router can
>> advertise that a prefix is not on-link - meaning that communications
>> between hosts in the same prefix must communicate via the gateway.
>> This can be the case in some non-broadcast networks, or networks
>> where device-device direct communications is blocked (e.g. for
>> privacy/security in public WiFi).
> 
> Very interesting, I didn't know that, thanks for the explanation!

There’s quite a bit different in IPv6 - it’s not just “extra address bits”. The opportunity was taken to fix some of the limitations found with IPv4 - such as the assumption that devices have a single address, and there’s only one subnet on each network, and all hosts in a subnet have direct communication. Unfortunately, as many people don’t realise that those problems exist, it’s seen as making it overly complicated.

I can recommend the free training available at https://ipv6.he.net/certification/ IMO Hurricane Electric have provided a great resource (including free IPv6 access via a tunnel over IPv4 https://tunnelbroker.net/). If you complete the certification program, you get what my local LUG members decreed to be the geekiest tee shirt ever made :-) Even if you don’t finish it, it worth the effort for the early stages where it introduces various aspects in a staged manner.


Simon



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