IPv6

IPv6 in general

IPv6 EUI-64

IPv6 address based on MAC address

• IPv6- How does a host get a global unicast with EUI-64 method
• Disable EUI-64 address generation
• EUI-64 and why you should not use it
• Why is the U/L bit inversed in EUI64?

Links

• https://wiki.archlinux.org/title/IPv6
• What’s the Deal with IPv6 Link-Local Addresses?
• IPv6 Address Representation and Address Types
• Global Unicast Address format
• Configure IPv6 Addresses And Basic Troubleshooting In Linux

DNS

Check delegation

dig 1.e.0.1.8.8.8.0.1.0.0.2.ip6.arpa ns

IPv6 on Linux

• Linux IPv6 HOWTO
• IPv6 on Debian
• http://www.cyberciti.biz/faq/debian-linux-ipv6-networking-configuration/
• http://ipv6.raphnet.net/

Configuring IPv6 on RedHat

In /etc/sysconfig/network-scripts/ifcfg-eth0

IPV6ADDRESS

Protocols and Acronyms

SLAAC

• SLAAC on Wikipedia

Neighbor Table

• Defining IPv6 Neighbors Information
• https://www.sciencedirect.com/topics/computer-science/neighbor-discovery

States

• Incomplete — Address Resolution is in process. The neighbor has not yet responded.
• Reachable — Neighbor is known to be reachable.
• Stale — Previously-known neighbor is no longer reachable. No action is taken to verify its reachability until traffic must be sent.
• Delay — Previously-known neighbor is no longer reachable. The interface is in Delay state for a predefined Delay Time. If no reachability confirmation is received, the state changes to Probe.
• Probe — Neighbor is no longer known to be reachable and Unicast Neighbor Solicitation probes are being sent to verify reachability.

NS

neighbour sollication

ND reachable time

how long will neighbour be reachable

NDP

Neighbor Discovery Protocol

DAD

       duplicate address detection

RA

Router advertisement

Sniff router advertisements

tcpdump -n -i eth0 icmp6 and ip6[40] == 134

global unicast address or GUA

http://www.tcpipguide.com/free/t_IPv6GlobalUnicastAddressFormat-2.htm

The part of the IPv6 address space set aside for unicast addresses is structured into an address format that uses the first 48 bits for the routing prefix (like a network ID), the next 16 bits for a subnet ID, and the final 64 bits for an interface ID (like a host ID).

Tools

• ipv6calc
• subnetcalc

FAQ

Can't ping link-local

ping -6: Invalid argument

or

Destination unreachable: Address unreachable

append "%eth0" or whatever interface name to the address