Re: Proxy VS Firewall

From: syN-acK (syN_acK_fiN@yahoo.com)
Date: 12/13/01 

From: syN_acK_fiN@yahoo.com (syN-acK)
Date: Thu, 13 Dec 2001 05:02:06 GMT

I think you are truly confused as to the difference between a proxy and a
caching server. They ARE NOT the same thing.

A proxy intercepts packets and processes them on the application layer. It is
actually the slowest way of processing data through a firewall, but some say
the most secure.

Microsoft calling their product Proxy server, and just because it caches does
not mean proxy=cache.

Gauntlet has lots of proxies, and doesn't cache a thing. So does WatchGuard,
and it doesn't cache. Checkpoint has proxies (they call them security servers,
so people won't yell 'What about stateful inspection?') and they don't cache
anything.

syN-acK

"mrleo" <mrleo@starband.net> wrote:
>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: ISA Server Problems, please help
    ... Based on the rules you have listed, SecureNAT clients should only be allowed ... The All access rule for SBS Internet Users ... Web Proxy and/or Firewall Client ... > header to the publishing server instead of the actual one. ...
    (microsoft.public.windows.server.sbs)
  • RE: Setting up a Proxy Server..
    ... Setting up a Proxy Server.. ... does, this works pretty well, and since workstation thinks it already got ... Since the internet requests from all the machines ...
    (Security-Basics)
  • Re: Is it true that All communication between front-end and back-end servers goes through TCP port
    ... from the article snip you provided, is that inter-server proxy communication ... OMA or Active Sync protocol requests forwarded to port 80. ... >> front end server. ...
    (microsoft.public.exchange2000.general)
  • RE: Simple ISA 2004 questions
    ... You'd better create a new GPO for IE proxy, ... Run "gpmc.msc" in SBS server, ... ISA Server 2004 Query can give you some help. ... In the Microsoft Internet Security and Acceleration Server 2004 console, ...
    (microsoft.public.windows.server.sbs)
  • Re: 0xc0040017 FWX_E_TCP_NOT_SYN_PACKET_DROPPED bei 2 Servern von 6
    ... Ich habe mir nun auf einem Server, der sich bei MS Updateservices bedienen konnte, WSUS installiert. ... Log Time Client IP Destination IP Destination Port Protocol Action Rule Client Username Source Network Destination Network HTTP Method URL Error Information HTTP Status Code Original Client IP Client Agent Authenticated Client Service Server Name Referring Server Destination Host Name Transport MIME Type Object Source Source Proxy Destination Proxy ... Connection Unrestricted Internet access anonymous Internal External HEAD ...
    (microsoft.public.de.german.isaserver)