Internet Connectivity  «Prev  Next»

Lesson 7Integrating Proxy Server into the Existing Network
ObjectiveDescribe how to select the Proxy Server interface characteristics that affect the integration of the Proxy Server into the network.

Integrating Proxy Server into the Existing Network

Depending on the size of the network, your network design can include a number of proxy servers. Each proxy server in the network design must have at least one interface. Specify one interface in the proxy server if the design requires only Proxy Server caching or if Proxy Server provides IPX to Transmission Control Protocol/Internet Protocol (TCP/IP) translation. This single-homed Proxy Server is contained entirely within the private network.

Selecting the Interface Address and Subnet Mask

When selecting the proxy server interface address and subnet mask, remember that:
  1. Each proxy server interface requires an IP address and subnet mask. This includes proxy servers that are accepting requests from internal network clients that are using IPX/SPX.
  2. The IP address assigned to the proxy server interface must be within the range of addresses that are assigned to the network segment that is directly connected to the interface. That is to say, the proxy server interface must be on the same subnet as the machines with which it needs to communicate directly.
  3. The subnet mask assigned to the proxy server interface must match the subnet mask that is assigned to the network segment that is directly connected to the interface.

Selecting the Interface data rate and the Persistence

Each proxy server interface connects to a private or public network segment. These network segments can be persistent or nonpersistent. The data rates for these network segments can vary considerably. You must specify the data rate and persistence for proxy server interfaces so that the proxy server can connect to private and public network segments. The following MouseOver discusses the interface characteristics for private and public network segments.

Internet Characteristics

Interface Characteristics for Network Segments
To connect to another location across the Internet, one solution is to specify a VPN tunnel over a DSL network segment. In this case, you will need to include a LAN interface that supports the persistent DSL network segment, and a demand-dial interface to perform the authentication required by the VPN tunnel.
The following paragraphs review public and private network segments.

Private versus Public - Network Segments

  1. Private network segments are based on local area network (LAN) technologies that are: persistent interface connections.
  2. Public network segments are based on: LAN and demand-dial technologies.
  3. To connect to another private network across the Internet, one solution is to specify: VPN tunnels instead of DSL network segments.
  4. Public network segments that appear as demand-dial interfaces are: nonpersistent interface connections.

Physical and Logical Layout

Before you can successfully configure a network for DHCP, you need to know the physical and logical layout of the network.
If you are fortunate, this information
  1. has already been recorded,
  2. is kept up-to-date, and
  3. you can actually find the necessary documentation.
If so, immediately track down the responsible administrator to obtain this information. If you are not so fortunate, grab a pen and notepad and start walking through the network. Make note of every hub or switch and how many devices are plugged into each. Work your way toward the server closet and record the number of routers or LAN router interfaces. Find the locations of any
  1. DNS servers,
  2. WINS servers, and
  3. any other servers that may require static addresses.
When you are finished, create a diagram of your results.
Next, determine which IP addressing scheme, if any, is currently in use on the network and add it to your sketch. If you are responsible for creating the addressing scheme, you will most likely be using one of the private range addresses:

In the next lesson, you will learn how to identify the client requirements to be included in a Proxy Server design.