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Annotated edit history of TransparentProxy version 7, including all changes. View license author blame.
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6 CraigBox 1 Transparent Proxying is when you use NetworkAddressTranslation to intercept traffic going to specific port and redirect it to go to a proxy. This is very popular in NewZealand [ISP]'s to redirect traffic to port 80 ([HTTP]) to a WebProxy, so they can attempt to proxy common content and save bandwidth (as all international traffic to/from NewZealand carries charges). The flaw in this plan is that while the proxy is supposed to be transparent (ie: you're not supposed to be able to tell it's there), far too often it becomes opaque, and you can tell that it's there. Common problems with Transparent proxies:
2 JohnMcPherson 2
3 * The source address is no longer your machine but the proxy, so any website that uses IP based authentication won't work.
4 * The source address may come from different IP's every time you request a page, so any website that remembers what IP your on and requires you to login each time you change it will ask you to login again always, sigh.
5 * The TransparentProxy accepts the connection, gets the request *then* goes and finds out if the page is available, so your browser doesn't get to handle events such as "Connection Timed out" or "Connection Refused"
5 JohnMcPherson 6 * The TransparentProxy resolves the destination host again which may be different to what your machine resolves it to, for instance if you use an AlternativeRoot[1], or have a /etc/hosts (hosts(5)) entry for the machine the TransparentProxy will either fail to find the [DNS] for it, or even worse, find its own one (which may be an old cached incorrect version).
3 PerryLorier 7 * Your [ISP] uses software that is not clever enough. For example, [Xtra]'s proxy (used to? still?) didn't look at the "Accept-Language" header. For example, if I send a request for the home page of www.debian.org with Accept-Language set to French, and you later send a request for the same page (but your browser sends a different language for Accept-Language) then you might get the French version if the proxy decides that the page is not yet expired. ''That would explain why I kept getting debian pages in french! Why couldn't you just read them in plain english like everyone else? <grin> -- PerryLorier''
2 JohnMcPherson 8
9 [1]: Not a good idea at the best of time anyway.
4 CraigBox 10
11 !But I want to do it anyway?
12
13 http://www.tldp.org/HOWTO/TransparentProxy.html
7 PaulWankadia 14 http://www.deckle.co.za/squid-users-guide/Transparent_Caching/Proxy
15 http://www.lesismore.co.za/Squid_3_Transparent_Proxy
5 JohnMcPherson 16
17 ----
18 Part of CategoryNetworking