Using the Proxy Server to Record IP Addresses When Resolving URL Masks

As stated earlier, you should include fully qualified DNS or hostnames in URL masks whenever possible.

The iChain Proxy Server resolves DNS names to their respective IP addresses and uses those addresses when pinning objects.

You can use this fact when constructing your pin list entries.

For example, if you use the DNS name www.foo.gov as the URL mask and you know that the DNS name foo.gov resolves to the same IP address, you don't need to include foo.gov in the pin list.

Because both URLs resolve to the same IP address, iChain Proxy Services will treat objects for both DNS names the same.

On the other hand, if www.foo.gov and foo.gov resolve to different IP addresses, separate pin list entries would be required to cover both sites.

Router Capabilities

Having the appliance double as a router impacts appliance performance, but it is a low-cost router option that delivers acceptable performance in some low-volume networks.

Each appliance is normally configured with a default gateway. If the appliance is not acting as a router, the default gateway is the appliance's next hop.

For more information about appliance routing, see Gateway/Firewall Tab and Routes Dialog Box.

Using Appliance Routing

If the appliance is acting as a router, it routes requests to IP addresses based on the information in its routing table. If a request could be routed through multiple gateways, the appliance chooses the gateway associated with the most restrictive mask (the smallest range of destination addresses).

Routing table entries fall within the following three basic groups:

• Host gateways for specific destination addresses
• Network gateways for destination addresses that fall within specific subnets
• The default gateway for destination addresses that aren't covered by host or network gateways

  The syntax for this gateway is often expressed in router configuration tables as 0.0.0.0 / 0.0.0.0 / iii.iii.iii.iii, where the i's represent the IP address of the default gateway.

You define these gateways in the browser-based management tool by clicking Network > Gateway/Firewall > Additional Gateways or by clicking Configure > Client Accelerator > Router Options.

IMPORTANT:  If the appliance is acting as a router and you don't specify a default gateway, the appliance routes only those requests whose destination addresses are covered by a host or network gateway. Other requests are not routed.

For more information on routing concepts, see one of the TCP/IP references available at any bookstore carrying computer reference manuals.