b20c:c011:5:b109::/64

Before I start with the actual configuration, a word on addressing.

I understand that I should use my own unique local unicast address (ULA) as defined in RFC4193 so that my network is compliant with best practice IPv6 implementations. ULAs are not expected to be routed on the global Internet.  They are routable inside of a more limited area such as a site.  They may also be routed between a limited number of sites.   ULAs are all part of the FD::/7 (officially FC::/7 with the lowest order bit set to one) network. Based on this, 2,199,023,255,55 /48 subnets can be defined.  The hope is that if organizations pick random /48 subnets, the chances of two companies who need to communicate directly with one another (communication between a limited number of sites) picking the same subnet are extreamly low.  This solves the problem currently present in IPv4 where most companies choose one of the RFC1918 networks and the chances of a collision are very high. Therefore, for B2B connections or mergers and acquisitions, IPv6 should be much better than IPv4.

So in that vain, I googled a tool to do just that and I got the following ULA from SixXS (www.sixxs.net): fdc1:e1f2:425d::/48.   I will subnet my networks into /64 subnets which will allow me to have 65’536 subnets.

The subnets I am using then are:

1. fdc1:e1f2:425d:1::/64 – Link between routers
2. fdc1:e1f2:425d:2::/64 – Host subnet (VBox Host Internal Network)
3. fdc1:e1f2:425d:3::/64 – Tunnel interface for ISATAP tunnel endpoint.

I configured all routers with a EUI-64 address for the host portion of the address, which is generated by the router automatically.  The EUI-64 address is generated as follows:

“For all IEEE 802 interface types (for example, Ethernet, and FDDI interfaces), the first three octets (24 bits) are taken from the Organizationally Unique Identifier (OUI) of the 48-bit link-layer address (the Media Access Control [MAC] address) of the interface, the fourth and fifth octets (16 bits) are a fixed hexadecimal value of FFFE, and the last three octets (24 bits) are taken from the last three octets of the MAC address. The construction of the interface ID is completed by setting the Universal/Local (U/L) bit—the seventh bit of the first octet—to a value of 0 or 1. A value of 0 indicates a locally administered identifier; a value of 1 indicates a globally unique IPv6 interface identifier.” ( see Cisco IOS IPv6 Configuration Guide, Release 12.4 for more information).