Default Gateway


A default gateway is the IP address of the router that the packets from a host should use to leave the subnet. The typical process of how a packet leaves a host and gets to a destination is as follows:

  1. Computer A looks up the IP address of Computer E by using a query to a DNS server.

  2. Computer A determines whether the IP address of Computer E is local or remote by comparing its own IP address to that of Computer E.

  3. If the address is remote, Computer E sends the packets to the default gateway's MAC address. The MAC address of the default gateway is determined via an Address Resolution Protocol (ARP) broadcast.

  4. The default gateway forwards the packets on to the next router, according to its routing table.

  5. If Computer E's IP address is on the same subnet as Computer A, the IP address of Computer E is resolved to the MAC address through an ARP broadcast.

  6. Computer A and Computer E communicate with one another, and there is no need for routing.

This section briefly explained the basics of TCP/IP, including its evolution, mechanics, and components. With this basic knowledge, you can move forward and configure TCP/IP on a Windows Server 2003 computer.

Challenge

You are a consultant who has been hired by Gidget's Widgets LLC, a small widget manufacturing company that has four departments. You have been hired by Gidget's Widgets to evaluate and recommend a design for a new Windows Server 2003-based network they plan to install in their new building. All computers on the network will be either Windows XP Professional or Windows Server 2003.

The president of Gidget's Widgets has told you that he wants each department to be on its own separate IP subnet with room for future growth. Each department must be on a separate IP subnet due to regulatory requirements imposed on the widget manufacturing industry. The company has three IP addresses assigned to it for external use by their ISP, but the company wishes to use IP addresses from the 192.168.100.0/24 private range for its internal needs. Should the company grow substantially and need additional IP addresses in the future, it will take them from the 192.168.101.0/24 subnet.

Each computer on the internal network is to be assigned its own statically configured IP address per the CIO's instructions. In cases in which there are more computers in a department than there are usable IP addresses in a subnet, two subnets may be assigned to the same department. For security reasons, a firewall will be used to prevent unauthorized inbound access to internal network clients from the Internet.

The departments and total number of computers are as follows:

  • Administration: 25 computers

  • IS: 45 computers

  • Engineering: 55 computers

  • Sales: 35 computers

Your task is to plan the required subnets for Gidget's Widgets using the IP range and instructions given to you by the president of the company.

Try to complete this exercise on your own, listing your conclusions on a sheet of paper. After you have completed the exercise, compare your results to those given in the following paragraphs.

Answers

You need to create four subnets from the given IP address block of 192.168.100.0/24. By applying the subnet mask 255.255.192.0 or 192.168.100.0/26, you can create these four IP subnets:

  • 192.168.100.1-192.168.100.62

  • 192.168.100.65-192.168.100.126

  • 192.168.100.129-192.168.100.190

  • 192.168.100.193-192.168.100.254

By using the VLSM /26, you create four valid subnets, each with a total of 62 usable addresses, allowing room for some growth on each IP subnet.

You can now assign each division its own subnets, as outlined here:

  • Administration: 192.168.100.1-192.168.100.62

  • IS: 192.168.100.65-192.168.100.126

  • Engineering: 192.168.100.129-192.168.100.190

  • Sales: 192.168.100.193-192.168.100.254





MCSA(s)MCSE 70-291(c) Implementing, Managing, and Maintaining a Microsoft Windows Server 2003 Network Infrastructure
MCSA/MCSE 70-291: Implementing, Managing, and Maintaining a Microsoft Windows Server 2003 Network Infrastructure (Exam Prep)
ISBN: 0789736497
EAN: 2147483647
Year: 2006
Pages: 196
Authors: Will Schmied

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