How to tell if an ip is a proxy?

[DartDave]

I understand how to tell where an ip traces to, for example, by running a "who is" on samspade.org. My question is, is there a simple way (or even a less simple way) to tell if an ip is a proxy or just a regular ol ip?<br />Thanks!!

[WiredGuy]

Hit the IP address... if it responds, chances are its a proxy. Try the common ports like 80 and 8080. Responding on those are usually proxies.<br /><br />WG

[DartDave]

By "hit the ip address" I assume you mean type the addy and port into the location bar and try to pull it up on my browser? For example, type<br />210.220.73.7:8080<br />Which gets me a funny error, but nonetheless a reply. So that one would be suspect.Other ips I just tested simply came back as no reply, so I'm assuming they're ok.<br /><br />Thanks tons for yer help, Wired Guy! Never thought it would be that simple! <img border="0" title="" alt="[Smile]" src="smile.gif" />

[SexySites]

One of the best ways to do it is to try and post a request through that ip address, that way if you get the page you requested you can tell if its a public proxy or not. This will probably not work for certain types of proxies.<br /><br />Otherwise its very hard to tell if an ip is a proxy, some of the request headers an ip will send will tell you if its a proxy or not, HTTP_VIA and X_FORWARDED_FOR for example, but anonymous proxies can hide these headers to hide the fact that they are even proxies at all.<br /><br />Quiet an ongoing discussion in this forum <img border="0" title="" alt="[Wink]" src="wink.gif" /> <br /><br />laters,<br />Chris