A firewall enhances security. A proxy server enhances performance.
According to the Webopaedia online dictionary (http://www.webopaedia.com/),
a firewall is "A system designed to prevent unauthorized access to or from
a private network. Firewalls can be implemented in both hardware and
software, or a combination of both. Firewalls are frequently used to
prevent unauthorized Internet users from accessing private networks
connected to the Internet, especially intranets. All messages entering or
leaving the intranet pass through the firewall, which examines each message
and blocks those that do not meet the specified security criteria."
And Webopaedia does a nice job with proxy server also: "A server that sits
between a client application, such as a Web browser, and a real server. It
intercepts all requests to the real server to see if it can fulfill the
requests itself. If not, it forwards the request to the real server.
Proxy servers have two main purposes:
Improve Performance: Proxy servers can dramatically improve performance for
groups of users. This is because it saves the results of all requests for a
certain amount of time. Consider the case where both user X and user Y
access the World Wide Web through a proxy server. First user X requests a
certain Web page, which we'll call Page 1. Sometime later, user Y requests
the same page. Instead of forwarding the request to the Web server where
Page 1 resides, which can be a time-consuming operation, the proxy server
simply returns the Page 1 that it already fetched for user X. Since the
proxy server is often on the same network as the user, this is a much
faster operation. Real proxy servers support hundreds or thousands of
users. The major online services such as Compuserve and America Online, for
example, employ an array of proxy servers.
Filter Requests: Proxy servers can also be used to filter requests. For
example, a company might use a proxy server to prevent its employees from
accessing a specific set of Web sites."
Cisco's PIX product is a firewall. Cisco also makes proxy servers. Check
out their cache engine and content distribution products. Also, check out
DistributedDirector and LocalDirector. More info here:
http://www.cisco.com/univercd/cc/td/doc/pcat/wbhw__d1.htm
My customers frequently confuse firewalls, proxy servers, and NAT servers.
I always correct them. ;-) I think it's important to distinguish these
logical functions, even if one box does them all. They have different
purposes. They help you realize different design goals.
Priscilla
At 10:38 AM 6/25/01, Jatin wrote:
>HI ,
>
>What is the difference between firewall and proxy server ?
>
>Which is better ?
>
>Does PIX support both ( Proxy and Firewall )
>
>Please help
>
>Thanks In Advance.
>
>Jatin
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=9830&t=9785
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