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Comment by bc569a80a344f9c

5 days ago

It’s not _that_ different. Larger address space, more emphasis on multicast for some basic functions. If you understand those functions in IPv4, learning IPv6 is very straightforward. There’s some footguns once you get to enterprise scale deployments but that’s just as true of IPv4.

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bc569a80a344f9c

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krupan  5 days ago

Lol! IPv4 uses zero multicast (I know, I know, technically there's multicast, but we all just understand broadcast). The parts of an IPv4 address and their meaning have almost no correlation to the parts of an IPv6 address and their meaning. Those are pretty fundamental differences.

  • bc569a80a344f9c  5 days ago

    IP addresses in both protocols are just a sequence of bits. Combined with a subnet mask (or prefix length, the more modern term for the same concept) they divide into a network portion and a host portion. The former tells you what network the host is on, the latter uniquely identifies the host on that network. This is exactly the same for both protocols.

    Or what do you mean by “parts of an IPv4 address and their meaning”?

    That multicast on IPv4 isn’t used as much is irrelevant. It functions the same way in both protocols.

morshu9001  5 days ago

The biggest difference is often overlooked because it's not part of the packet format or anything: IPv4 /32s were not carried over to IPv6. If you owned 1.1.1.1 on ipv4, and you switch to ipv6, you get an entirely different address instead of 1.1.1.1::. Maaybe you get an ipv6-mapped-ipv4 ::ffff:1.1.1.1, but that's temporary and isn't divisible into like 1.1.1.1.2.

And then all the defaults about how basically everything works are different. Home router in v6 mode means no DHCP, no NAT, and hopefully yes firewall. In theory you can make it work a lot like v4, but by default it's not.