IPv6 Fundamentals Tutorial (part 2)

4. Router Advertisements

  • The Network is in Control of addressing via Router Advertisements (RAs)
    — Controls SLAAC (a-bit), and/or DHCPv6 (m-bit), or Other bit (o-bit)
    —  Auto Configuration Options
  • RAs are periodically sent out by the router to all nodes (FF02::1)
  • RAs are an ICMPv6 message type
  • Sends Domain Name Server (DNS) information in the Recursive DNS Server (RDNSS) field
  • Sends MTU size
  • Sends the default gateway address (usually the link-local address of the router)

5. DNS is your friend

  • Unless you have a very young brain, remembering hexadecimal addresses is going to be a challenge.
  • Quad A records (AAAA) are IPv6 address records
    —  AAAA records can be returned to the requester over IPv4 or IPv6
  • ping6 by name rather than IPv6 address

Hands On

Attempt/Answer the following:
* What Prefixes are being advertised by the router?
* Are the M, O, or A bits set?
* What is the IPv6 default gateway of your “PC”?
* Can you ping6 the router? Can you ping the router’s link-local address?
* How many IPv6 addresses does google.com have?
* Use wireshark (or tcpdump) to see the DNS query/reply, what network protocol was used?

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