Comment by heavyset_go

5 days ago

> - It's hard to remember IPv6 addresses. The prospect of reconfiguring all my router and firewall rules looks rather painful.

fd00::1 is pretty easy to remember. It's your network, give yourself a sane and short prefix.

21 comments

heavyset_go

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Hobadee  5 days ago

That's a gripe I have with IPv6. There are too damn many special networks and addresses!

With IPv4 I can easily remember 10.0.0.0/8 and 192.168.0.0/16, but I can't remember the other one off the top of my head. (172.16.0.0/12 I think?). Multicast is 224.x.x.x/x IIRC, but definitely need to look that one up when I need it.

IPv6 has SO many special networks. Network. Public. Multicast. Link local. (Which isn't like an IPv4 link local, but apparently it can actually be on the LAN? IDK - I was just learning about it earlier today.) And every interface seems to have about 5 different addresses of each type.

  • oarsinsync  4 days ago

    Amusingly, there a lot more special IPv4 networks that you just don't know about too. e.g. Link local IPv4 is 169.254.0.0/16. It just isn't auto-configured on every IPv4 interface by default, like fe80::/10 is on IPv6 interfaces, and the TCP/IP stacks on most platforms do not enforce the link-local properties of it in IPv4 like they do in IPv6.

    It's like the difference between HTML and a strictly typed language. Permissiveness and flexibility is both a blessing and a curse. As with a lot of things, which thing it is in any given situation depends greatly on the situation.

  • 9dev  4 days ago

    For almost all cases, there is absolutely zero need to ever remember addresses, or dealing with them directly. Give your devices proper names, and your router’s DNS will handle resolution automatically.

    There is no point in your network having sequential addresses, so you don’t need DHCP; routers advertise configuration, clients know where to look for it.

    IPv6 is amazing, if you let it handle connectivity without trying to micromanage it.

    • Ekaros  4 days ago

      I think this is the big hangup. Wanting to micromanage each and every address. Instead of letting it just manage itself. Reminds me on some level of the pet vs cattle of containers and servers. Mental switch is needed. And many are resistant towards this.

      2 replies →

  • patmorgan23  4 days ago

    You forgot 127.0.0.0/8 for loopback, 100.64.0.0/10 for CG-NAT, and 203.0.113.0/24 and 0.0.0.0/8

  • ozim  4 days ago

    Why do you need to remember that when you can look it up?

    Important part is knowing there are special networks.

  • throw0101a  4 days ago

    > IPv6 has SO many special networks. Network. Public. Multicast. Link local.

    IPv4 has those exact same ones: link-local (169.254/16), multicast (224/4), public, private (RFC 1918).

    * https://en.wikipedia.org/wiki/Reserved_IP_addresses

    IPv6 is (IMHO) simpler: 2001::/32 and anything else (either link-local (fe80), multicast (ff00), and ULA (fc)). So either it starts with a "2" or an "f".