Proxy VS Firewall

From: mrleo (mrleo@starband.net)
Date: 12/13/01 

From: "mrleo" <mrleo@starband.net>
Date: Thu, 13 Dec 2001 02:39:21 GMT

Hey first off, just my two cents here.

    Proxy is defined as a web page caching server *NOT* a firewall. a proxy
(MS Version) does nothing but *hide* your internal network and cache web
pages from the rest of the world. Yes you can define the list of allowed
"protocols" that have the access to be able to pass through the proxy server
itself, however there is no such thing as a packet filter to verify that the
sender is allowed to connect

Firewall however will do things such as application filter's, packet
filtering.But it DOES NOT cache web pages.

 Yes there may be some small similarity between the 2, however they should
not be viewed as the same type of product.

Even some personal software on the market may infact perform both functions
( Winproxy) This program does both it caches web pages and has a limited
built in firewall.

Webopedia Defition

Firewall

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

Packet filter: Looks at each packet entering or leaving the network and
accepts or rejects it based on user-defined rules. Packet filtering is
fairly effective and transparent to users, but it is difficult to configure.
In addition, it is susceptible to IP spoofing.
Application gateway: Applies security mechanisms to specific applications,
such as FTP and Telnet servers. This is very effective, but can impose a
performance degradation.
Circuit-level gateway: Applies security mechanisms when a TCP or UDP
connection is established. Once the connection has been made, packets can
flow between the hosts without further checking.
Proxy server: Intercepts all messages entering and leaving the network. The
proxy server effectively hides the true network addresses.

Proxy

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.

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.

Relevant Pages

  • Re: How to allow for programs through ISA 2000
    ... Network Proxy Server such as ISA Server. ... firewall or proxy server to perform Smart Update, ...
    (microsoft.public.isa)
  • RE: Proxy & Firewall Implementation
    ... go through the firewall from that machine. ... if it's a decent size network they are ... outside the network in a dmz, is to protect the rest of the network ... circumstances when placing their proxy server inside a protected network ...
    (Security-Basics)
  • Re: Proxy VS Firewall
    ... >>Firewall however will do things such as application filter's, packet ... Looks at each packet entering or leaving the network and ... >>Proxy server: Intercepts all messages entering and leaving the network. ... It intercepts all requests to the real server to see if it ...
    (comp.security.firewalls)
  • Can connect VISTA BUSINESS to SBS 2003
    ... We bought a VISTA business pc about a year ago and getting it onto our SBS network was unbelievebly complex ... One had XP on and joined the network in 30 seconds. ... If you use a public proxy server to browse the Internet, clear the Internet Explorer connection setting for using a proxy server. ...
    (microsoft.public.windows.server.sbs)
  • Re: ActiveSync Freezes with Internet setting applied
    ... detect if you have a proxy server on your network. ... This is controlled by the connection settings. ... The active sync comes back as not responding, ... the check box is cleared or the network cable is unplugged. ...
    (microsoft.public.pocketpc.activesync)