On 26/08/2015 2:33 p.m., SaRaVanAn wrote: > Hi All, > I have a basic question on Client - web server communication through Squid > using transparent proxy. > In case of transparent proxy Whenever a client tries to access a webpage, > squid spoofs the packet and acts like a web server. In turn Squid initiates > a new TCP connection with the web server. > My clarification is like whether squid initiates a new TCP connection with > webserver as soon as it receives a SYN packet from the client or after a > TCP session has been established between the client and squid proxy server. > I both the > > Client Squid Webserver > > SYN > -------------------------> > SYN+ACK > <------------------------ > ACK > ---------------------------> > > HTTP GET > ------------------------------> > SYN > Not quite. Squid doesn't act like a web server exactly. It just avoids using the proxy-only HTTP features in messages visible to the client. For all other intents and purposes it is still a proxy and doing proxying for this traffic. Which partially answers your question. Since Squid is proxying these messages - no, there is no server connection opened until one is needed. After the caching logics have checked for HITs, adaptation and re-writing checked for early responses/errors etc, and routing logics decided what server(s) to try going to. The spoofing of the client IP on TPROXY only affects the routing logics by adding a restriction: only server accessible to the client are usable. Original dst-IP of the server the client was trying to reach is also preferred over others for a more seamless/invisible/transparent service and is the most likely to succeed on first-try. But other destinations selected by the routing logics could easily be used if that fails. Amos _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
