Hierarchies of proxies

Hierarchies of proxies
	Chapter 3. The SQUID proxy server

We have covered the basics of getting your proxy server up and offering better response to your clients.

Proxies can operate in a hierarchical manner. Supposing your ISP has a proxy that stores HITS from all their clients. Clearly, their proxy will be larger than yours since they most probably have more client workstations 'hitting' it on an hourly basis. What would be nice is to use their proxy as well as yours. Thus, if a web page is not cached on your proxy, your proxy would query the ISP's proxy to see whether it has the page cached in it's tree. If so, it has saved you time and possibly money, as this may be an international site that is cached, and many ISP's in South Africa have differing rates depending on whether the sites you visit are local or international.

The configuration of hierarchical proxies is well outside of the bounds of this course, and of course you would need another proxy on the network in order to see the effect of this, but at least you know the functionality is there and can be configured at some future date.

In a future update on this course, I will include configuration of squid to handle authentication of users.

Exercises:

Configure squid to allow access to the internet for your network. Assume your network is in the IP address range 168.158.14.x. You would disallow the workstation 168.158.14.24 access to the Internet as they have been known to be malicious in the past. Deny all FTP access out of your network.
Ensure that you squid server has a minimum of 200Mb of space allocated to the cache and ensure that a minimum of 32 directories are created on startup at the tier-1 level. Tier-2 should have the standard 256 directories.