Before leaving the subject of TCP/IP administration, we should introduce IP Version 6. IP Version 4, which is the current version of IP used, provides a 32-bit addressing system (as represented by the four octets in the dotted decimal format of an IP address). This supplies more than 3,560,000,000 total addresses.
The problem with IP Version 4 is that the IP address pool has been nearly exhausted. This is amazing, considering that even as little as 10 years ago, no one would have imagined the possibility of running out of unique IP addresses.
IP Version 6, which will become more prevalent as time goes by, uses a 128-bit addressing system that provides 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses. This is a very large number of IP addresses, and it will be difficult to exhaust this pool.
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The IP Version 6 address is a hexadecimal address that consists of eight 16-bit parts . A sample address is FEDC:BA98:7654:3210:FEDC:BA98:7654:3210.
A number of new server products such as Windows Server 2003 and Novell NetWare provide support for IP Version 6. IP Version 6 is also compatible with Version 4, and the two can cohabitate on a network with no problems.
While the Internet Engineering Task Force (IETF) has had specifications for IP Version 6 in place since the late 1990s, there has not yet been a stampede to adopt this new IP addressing scheme. It should be phased in over the next couple of years, which means that subnetting and addressing concerns will change dramatically to accommodate the new address format.
The Absolute Minimum
In this chapter we had the opportunity to take a look at some of the issues related to administering a TCP/IP network. We discussed configuring IP addresses, DHCP, DNS, routing, and IP subnetting.
Computers on an IP network must be configured with an IP address, subnet mask, and other TCP/IP settings such as default gateway, DNS server address, and WINS server address.
The Dynamic Host Configuration Protocol (DHCP) can be used to supply DHCP clients with IP addresses, subnet masks, and other TCP/IP settings dynamically. A DHCP server leases the IP addresses to the DHCP clients .
The Domain Name System (DNS) provides the logical hierarchy for the Internet and TCP/IP networks. A DNS server is able to resolve the DNS friendly name (the name as determined by the DNS hierarchy for the network) of a device to an IP address (and vice versa).
DNS servers field requests from devices on the network for resolving DNS names to IP addresses. A forward lookup zone is required on a DNS server and holds the A records that provide a device's DNS name and its IP address. Reverse lookup zones on a DNS server hold records that allow IP addresses to be resolved to friendly names .
An internetwork is a network of networks. Routers are used to connect LANs into an internetwork. Each segment or subnet of the internetwork is connected to a router interface. The router uses a routing protocol to build routing tables. These routing tables are used to route the data from the subnets to the appropriate destinations.
IP subnetting allows you to borrow bits from a network address and create logical subnets. The creation of the subnets requires that a new subnet mask be computed for the network and that subnet address ranges be created to be assigned to the devices on each subnet of the network.