How Proxy Server Works

Benefits of Proxy Server

Benefits of using Proxy Server include security, shared bandwidth, increased client functionality, caching, Web publishing support, industry standards support, and integration with Windows NT Server and IIS.

Firewall Security

Proxy Server prevents unauthorized external access to your private network and hides internal IP addresses from the Internet. It provides user -level security and Windows NT Challenge/Response authentication. Data encryption is supported by means of Secure Sockets Layer (SSL) tunneling. Proxy Server offers the following security benefits:

• The Proxy Server processes all incoming and outgoing requests .
• You can enable and configure either dynamic or static packet filtering.
• You can control access to the Internet from the LAN.
• You can limit access from the LAN to specific Internet sites.
• You can limit Internet usage to specific services and/or ports (such as allowing only FTP, Telnet, and HTTP).

Shared Bandwidth

Instead of each client having a separate line to the Internet, many clients can use a common connection. For example, a company with 20,000 employees could provide each employee with an analog phone line and a 28.8 bits per second (bps) modem for Internet access. In addition to the cost of setting up the phone line and purchasing the modem, you would incur additional monthly fees for the phone lines and ISP connections for each employee.

Alternatively, this same company could lease a 10-MB (T3) line for a set monthly fee and give each employee faster, more reliable access to the Internet.

In a less extreme example of shared bandwidth, a small company using multiple dial-up lines for Internet access could switch to a single ISDN line and share access through Proxy Server. Using Proxy Server you can monitor Internet use more effectively than using multiple dial-up lines.

Internet Applications Extended to Every Client Desktop

All desktop clients on a LAN can easily access the Internet and run most WinSock and SOCKS applications by using either IPX/SPX or TCP/IP through Proxy Server. Only the computer running Proxy Server needs an IP address.

Proxy Server Caching

Commonly accessed HTTP and FTP sites can be cached on a single Proxy Server computer or on a distributed cache spread across multiple Proxy Server computers. This can improve the response time for clients and reduce the amount of traffic to the Internet.

Proxy Server offers two forms of distributed caching: arrays and chaining.

• Arrays allow a group of Proxy Server computers to be administered as a single, logical entity. It provides load balancing, fault tolerance, and scalability. For example, client performance is improved by allowing caches to be located at the workgroup level instead of remaining at the enterprise level. And as your organization's needs grow, you can improve network performance by adding additional Proxy Server computers to the array.
• Chaining is a hierarchical connection of several Proxy Server computers. It improves fault tolerance and distributes the server load by forwarding client requests "upstream" through the chain until the requested object is found.

Web Publishing Support

Proxy Server allows information to be published to the Internet without compromising the security of your internal network. This publishing support is provided through reverse proxying and reverse hosting:

• Reverse proxying allows Proxy Server to listen and respond to requests on behalf of a Web server, effectively "impersonating" the Web server on the Internet.
• Reverse hosting adds flexibility to reverse proxying by allowing multiple Web servers to publish to the Internet.

Industry Standards Support

Proxy Server supports many industry standards including:

• HTTP
• Windows Sockets
• SOCKS version 4.3a
• SSL

Integration with Windows NT Server and IIS

Proxy Server integrates with the networking, security, and administrative interfaces of the Windows NT Server operating system and Internet Information Server (IIS). This allows Proxy Server to take advantage of the administration, performance, and scalability benefits offered by Windows NT Server and IIS.

Lesson Summary

Proxy Server is a network component that provides a secure gateway between the Internet and a secured LAN. It can connect groups, divisions, or an entire intranet to the Internet. The benefits of using Proxy Server include:

• Firewall security
• Shared bandwidth
• Internet applications extended to every client desktop
• Proxy Server caching
• Web publishing support
• Industry standards support
• Integration with Windows NT Server and IIS