From Network Programming in .NET: With C# and Visual Basic .NET

7.1 Introduction

This chapter deals with the practical issues of setting up a network and network architecture in general. Knowing how networks differ from a programmatic perspective can help fix a lot of network-application-related bugs. Furthermore, basic working knowledge of network setup is essential in the day-to-day life of many developers.

This chapter is structured in two sections. The first section explains how to create a network from autonomous, stand-alone machines. Immediately following that is a discussion of common devices that form gateways between your network and the Internet. These gateway devices can often create problems for your software by imposing their own restrictions and regulations. By being able to detect and work around these problems, your application will be more stable in a mass-market environment.

7.1.1 Building a Network from Scratch

If you are developing a point-of-sale system for a supermarket, each terminal will need to communicate with a central server to consolidate the day's takings and process stock levels. This is not easily achievable without a network. In many cases, you can't just give a shopkeeper a CD and expect him to figure out how to get every computer in his business tied to a single network.

Choosing a Topology

If you have only two computers that you want to network, and there is no need for a third, then the most economic solution is a unshielded twisted pair (UTP) crossover cable (not UTP patch cable). This can be used to link two computers directly.

There are three...

Products & Services
Network Wiring and Cabling Services
Network wiring and network cabling services install copper and fiber optic cable within buildings or central offices.
Network Firewalls
Network firewalls protect computer networks against unauthorized use or attack. They permit or deny access to private network devices and applications, and represent an important part of an organization's overall security policy. Firewalls may be software applications, hardware devices (such as routers), or a combination of both. They include turnkey products that are relatively easy to install as well as complex, multi-layer installations that require the expertise of a certified network administrator. 
Network Bridges
Network bridges connect network segments so that devices on both segments can communicate as if they were part of the same network. The centralize network administration and are easier to configure than network routers, which require IP addressing for each computer on each segment.
Network Gateways
Network gateways interconnect networks with different, incompatible communication protocols. They perform a Layer-7 protocol-conversion to translate one set of protocols into another (for example, from TCP/IP to SNA or from TCP/IP to X.25).
Network Security Software
Network security software includes everything from remote access protection to firewall and security appliance solutions to email security to web filtering, monitoring, bandwidth protection, and all elements of computer network security/computer security.

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