Beginner facts about IPv6


Success with IPv6

  • This is an IPv4 address in hexadecimal: FF.FF.FF.FF (

  • This is an IPv6 address, which are always in hexadecimal: FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF. See the difference in size?

  • Everyone gets public IPv6 addresses. There is no need for NAT.

  • I'll say it again, there is a no need for NAT. Firewalls still work, but don't use NAT.

  • No NAT means end to end communication with less complexity. Rejoice!

  • You will be assigned a large subnet of public IPv6 addresses. No more rationing a handful of public IPs.

  • The smallest typical subnet of IPv6 is a /64 or 264 addresses. IPv4 space, all of it contains 232 addresses.

  • Small organizations, or even your home, are assigned a /56 which contains 256 /64 subnets.

  • Larger organization are assigned a /48 which contains 65535 /64 subnets.

  • Go back and count those in your head again. I'll wait.

  • Sipcalc is a good IPv6 subnet calculator.

  • Addresses can be statelessly assigned to nodes using SLAAC.

  • Addresses can be assigned statefully using DHCPv6.

  • IPv6 and IPv4 are separate protocols and co-exist. This is called dual stack.

  • You must have separate routing and firewall rules for both IPv4 and IPv6.

  • Services must be configured to listen on IPv6, but most do so by default already.

  • A DNS A record for an IPv6 address is an AAAA or 'quad A' record. dig aaaa

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