Obtaining an IP Address

To obtain an IP address for your company to use, you can contact InterNIC (the Internet Network Information Center) and purchase one. Most Class A addresses are not available because they were gobbled up by the military and universities when the Internet was first established. If you purchased a Class C address, the first three octets would be the network ID your company would use, and you could then add up to 254 host computers to your network segment. Why 254 Because only one octet is...

Classless Internet Domain Routing CIDR

In the classful method of IP addressing, the number of networks and hosts available for a specific address class is predetermined by the default subnet mask for the class. As a result, an organization that is allocated a network ID has a single, fixed network ID and a specific number of hosts. With the single network ID, the organization can have only one network connecting its allocated number of hosts. If the number of hosts is large, the network will not be able to perform efficiently. To...

Creating a Redundant Infrastructure

When you design a system that gives your company access to the Internet, you might want to consider having more than one way to connect to the Internet, especially if your company relies on this connectivity to do business. However, just as a security professional would not spend 50,000 to protect a company's data that is worth 5,000, you should consider the cost of your redundant system as it relates to the value of downtime or the inability to connect to the Internet. For example, if a...

NetBIOS Name Resolution Overview

In the early eighties, Sytek Corporation developed NetBIOS for IBM to enable their applications to communicate over a network. After twenty years, many applications are still using NetBIOS. Previous versions of Windows used NetBIOS names to identify resources that were on a network. A NetBIOS name is a 16-byte address used to identify a network resource, just as a host name identifies resources on a TCP IP network. The first 15 characters of the NetBIOS name are specified by the administrator,...

Subnetting Your Network

Recall that a Class C address uses the first three octets as the network portion of the address and leaves the remaining 8 bits, the last octet, for host addresses. If you want to split this Class C address into two network addresses, you need to borrow some of those host bits. This borrowing of bits from the host portion of an IP address is called subnetting. How many bits you borrow from the host portion of an IP address is determined by the following How many subnets do you need to create...

Page Lesson Review

List the five different address classes and the value of the first octet. Also, list each of the private IP addresses available for internal use by a company. The five different address classes and the value of the first octet are as follows A (1-126), B (128-191), C (192-223), D (224-239), and E (240-255). The private addresses available for internal use are 10.0.0.1-10.255.255.254, 172.16.0.1-172.31.255.254, and 192.168.0.1-192.168.255.254. 2. Your company has more than 15,000 workstations...

Key Terms

Zone A zone is a contiguous portion of a DNS tree that is administered as a separate entity by a DNS server. Zone transfer A process in which DNS data is replicated from one DNS server to another. There are three types of zone transfers in Windows Server 2003 IFXR, AXFR, and fast zone transfer. Caching-only server A DNS server that caches the answers to queries and returns the results. This saves time and reduces network traffic because calls to multiple DNS servers are not required. BIND...