TCP and UDP

• Describe TCP and UDP, and how they differ. Why do both protocols exist?

Address Types

• In your own words, briefly describe each of the address types mentioned in LabSim (Global-Unicast Addresses, Unique-Local Addresses, Link-Local Addresses, Multicast Addresses), and provide a scenario when each is useful for an organization. In particular, differentiate link-local, unique local and global addresses.

ISATAP vs. 6to4 vs. Teredo

• LabSim describes the ISATAP, 6to4 and Teredo transition technologies for IPv6. In your own words, define one (in a way that differentiates it from the others). Then, do one of the following:

o Describe a realistic scenario (with some details) for using the technology you chose
o Locate a case study or other online article (of that technology or IPv6 transition in general) and provide your thoughts on it
o If your organization is undergoing (or underwent) an IPv6 transition, discuss some of the details.

A Global-Unicast address is an address on the Internet.
Unique-Local, previously referred to as Site-Local, indicates a private IP Address.
Link-Local indicates that the IP address was configured by default.
Multicast indicates that the packet is addressed to a number of hosts on the network, but not all hosts.

ISATAP: The Intra-site Automatic Tunnel Addressing Protocol (ISATAP) is a tunneling method for use within a site to provide IPv6 communication over a private IPv4 network. ISATAP tunneling:

• Is configured between individual hosts and an ISATAP router.

• Requires an IPv6 router to perform tunneling, and dual layer or IPv6-only clients. Routers and hosts perform tunneling when communicating on the IPv4 network.

• Does not work through NAT.

• Automatically generates link-local addresses that includes the IPv4 address of each host:

o The prefix is the well-known link-local prefix: FE80::/16.

o The remaining prefix values are set to 0.

o The first two quartets of the interface ID are set to 0000:5EFE.

o The remaining two quartets use the IPv4 address, written in either dotted-decimal or hexadecimal notation.

A host with an IPv4 address of 192.168.12.155 would have the following IPv6 address when using ISATAP: FE80::5EFE:C0A8:0C9B (also designated as FE80::5EFE:192.168.12.155).

Use ISATAP to begin a transition to IPv6 within a site.

• You can start by adding a single ISATAP router and configuring each host as an ISATAP client.

• Vista clients will use ISATAP automatically if they can find the ISATAP router.

Vista clients query the DNS server for a router named ISATAP. When using ISATAP, be sure to use this name for the server, or create an A or CNAME record in DNS using ISATAP as the name and pointing to the ISATAP router.

6-to-4 tunneling: With 6-to-4 tunneling, tunneling endpoints are configured automatically between devices. 6-to-4 tunneling:

• Is configured between routers at different sites.

• Requires routers that provide dual layer support as the tunnel endpoints. Hosts can be IPv6-only hosts.

• Works through NAT.

• Uses a dynamic association of an IPv6 site prefix to the IPv4 address of the destination tunnel endpoint.

• Automatically generates an IPv6 address for the site using the 2002::/16 prefix followed by the public IPv4 address of the tunnel endpoint router. For example, a router with the IPv4 address of 207.142.131.202 would serve the site with the following prefix: 2002:CF8E:83CA::/48 (CF8E:83CA is the hexadecimal equivalent of 207.142.131.202).

Use 6-to-4 tunneling to dynamically connect multiple sites through the IPv4 Internet. Because of its dynamic configuration, 6-to-4 tunneling is easier to administer than manual tunneling

Teredo: Teredo (also known as NAT traversal or NAT-T) establishes the tunnel between individual IPv6 hosts so they can communicate through a private or public IPv4 network. Teredo is a last resort technology in that it is used only when there is no native IPv6, ISATAP, or 6-to-4 connectivity present between hosts. Teredo tunneling:

• Is configured between individual hosts.

• Has dual layer hosts that perform tunneling of IPv6 to send on the IPv4 network.

• Works through NAT.

• Uses a 2001::/32 prefix followed by the IPv4 public address converted to hexadecimal. For example, the IPv4 public address of 207.142.131.202 would provide clients with a prefix of 2001:0:CF8E:83CA::/64.

For Windows Vista and Windows 7, the Teredo component is enabled but inactive by default. In Windows Server 2012, Teredo is enabled by default only on non-domain networks (it is disabled by default on Windows Server 2008 and 2003 SP1). To use Teredo, a user must either install an application that needs to use Teredo, or configure the advanced settings on a Windows Firewall exception to use edge traversal.

Teredo behavior differs when machines are members of a domain. Teredo is disabled on XP and Server 2003 machines that belong to a domain. Teredo is enabled on Vista and 2008 machines that belong to a domain. Teredo is disabled by default on Windows 8 and Windows Server 2012 machines that are part of a domain.