Transparent Proxiy Cache And Ntl - Page 2

**Paul** · 12-06-2006, 18:09

Among others, yes.

melevittfl · 13-06-2006, 07:02

Quote:

Originally Posted by codebreaker

Now the question is can a customer use the NTL line to query a 3rd party DNS server ? . Will a freeserve DNS server do the job of resolving a web URL into an IP address for an NTL customer ? .

Normally yes.

Listen, if you really want to understand how all this works, I would suggest picking up a copy of "TCP/IP Illustrated Vol 1." by Stevens.

http://www.amazon.co.uk/exec/obidos/...228362-2512641

westy · 13-06-2006, 13:27

What DNS server you use has nothing to do with the proxies. a URL has nothing to do with the underlying workings of the internet. As soon as you type a URL the DNS specified in your settings will be queried for the IP address of the domain. Your browser will then issue it's first packet with a SYN header flag set to that IP address with a destination port 80. Your browser thinks its trying to establish a connection to the correct place. (once a connection is established via IP the actual english that is the URL you typed originally is then passed as data within packets for the remote server to deal with)

Basically the proxies are just intercepting all packets aimed at any IP address with the destination port of 80, the proxy will then accept the connection and deal with the request by either sending the page back if it's got it or fetching it from the originating source if it hasn't.

So in other words there's no way to avoid them unless you specify a different proxy server in your browsers settings... but that defeats the whole object of a straight look-up.