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Network Configuration—IPv6FreeBSD uses the IPv6 code from the KAME project. The KAME project(see www.kame.net) has been inactive since 2005, and FreeBSD developers haveeversince maintained the IPv6 protocol stack.In this chapter, we will look into the following:• IPv6 facts• Using IPv6• Routing IPv6• RIP6• Multicast routing• TunnellingIPv6 FactsIf you are not familiar with IPv6, here is a very quick look at the difference betweenIPv4 and IPv6. (For a more detailed insight into IPv6 and its configuration in variousoperating systems, it is recommended that you read Running IPv6 book by Iljitschvan Beijnum).Fact One—AddressingAddressing in IPv6 is quite different from legacy IPv4 addresses. IPv6 uses 128-bitaddress space unlike the 32-bit addressing system in IPv4. A typical IPv6 addresswould look like—2002:a00:1:5353:20a:95ff:fef5:246eFact Two—Address TypesThere are 4 types of addresses in IPv6:• Unicast: A typical IPv6 address you use on a host.• Multicast: Addresses that start with ff:: are equivalent to IPv4 multicast.• Anycast: A typical IPv6 address that is used on a router.• Reserved: Includes loopback, link-local, site-local, and so on.Fact Three—ARPThere is no ARP! MAC to IP mapping is no longer needed as MAC addresses areembedded into IPv6 addresses. Instead, ND is born. ND is used to auto-configureaddresses on hosts, duplicated detection, and so on.[ 176 ]