What is a proxy?

Just to clear up something regarding proxies...

What is a proxy?
I have an idea that when you set it up, it hides your ip address...that's all i know.

Any more "formal" definition out there?

MiCr0

Proxy Server----Defination

In an enterprise that uses the Internet, a proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from outside intrusion.

A proxy server receives a request for an Internet service (such as a Web page request) from a user. If it passes filtering requirements, the proxy server, assuming it is also a cache server, looks in its local cache of previously downloaded Web pages. If it finds the page, it returns it to the user without needing to forward the request to the Internet. If the page is not in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses to request the page from the server out on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it on to the user.

To the user, the proxy server is invisible; all Internet requests and returned responses appear to be directly with the addressed Internet server. (The proxy is not quite invisible; its IP address has to be specified as a configuration option to the browser or other protocol program.)

An advantage of a proxy server is that its cache can serve all users. If one or more Internet sites are frequently requested, these are likely to be in the proxy's cache, which will improve user response time. In fact, there are special servers called cache servers. A proxy can also do logging.

The functions of proxy, firewall, and caching can be in separate server programs or combined in a single package. Different server programs can be in different computers. For example, a proxy server may in the same machine with a firewall server or it may be on a separate server and forward requests through the firewall.

Hehe, now that's a formal definition!

Thanks Micro!

The Corinthian

If you consider everything as either a Client (something that sends out a HTTP Request and receives/processes a HTTP Response) or a Server (something that receives/processes a HTTP Request and sends out a HTTP Response), then a proxy is both.

Generally what a proxy will do is sit between a client and server and relay traffic between them, carrying out some form of process or other to either the Request/Response along the way. The classic example of a proxy is a firewall - all requests pass via the proxy (firewall), which may also be set up to monitor outgoing traffic. It passes the Request on to the requested Server, which responds to the proxy. At this point the proxy will examine what’s been returned and filters out harmful content, before sending it back to the original Client (admittedly the majority of the work done by a firewall is by filtering Requests from without, but it’ll do this too and anyway we’re discussing proxies here). Other examples of proxies can be relays, WAP/I-Mode gateways and even some bots.

In short, a proxy is a Client/Server hybrid that filters or translates HTTP traffic passing through it.

Could you use proxies to hide your IP address during IRC sessions?

That's one thing i'd like to be able to do.

The Corinthian

Originally posted by MoonHawk
Could you use proxies to hide your IP address during IRC sessions?

Yes. But remember that the proxy will know your real IP address.

Originally posted by MoonHawk
That's one thing i'd like to be able to do.

No doubt up to no good...

moist

Originally posted by The Corinthian

The classic example of a proxy is a firewall - all requests pass via the proxy (firewall), which may also be set up to monitor outgoing traffic.

Erm... No!
A proxy works in the application layer whereas a Firewall works on the network layer.
Granted there are firewall products that _also_ have application layer products, but still.

The Corinthian

Originally posted by moist
Erm... No!
A proxy works in the application layer whereas a Firewall works on the network layer.
Granted there are firewall products that _also_ have application layer products, but still.

I did alude to the fact that it wasn't a perfect example, but a lot of firewalls do act as http proxys too, and I was mainly looking for a 'friendly' example.

Yes. But remember that the proxy will know your real IP address

I don't mind that, as long as i can still use irc with the proxy.

No doubt up to no good...

Not at all...the only reason i've never used IRC is because that anyone can find out your IP address...i don't like that, so i never really got into it, preferring web chats.
But if i could use a proxy to hide my ip address, then i could use IRC more...get into it, more chat rooms on that then on usual webchat pages.