Why we set the Proxy setting on Localhost?

[aysha]

hi
Why we set the Proxy setting on Localhost when ever we want to use any testing Tool like e.g WAPT for performance testing and PAROS for security testing, both tool dont work until i set the proxy setting on local host

please explain me why we have to do this

aysha:P

[WSFuser]

localhost (sometimes written as 127.0.0.1) loops back the tests to ur computer. if a different address was entered, then that other computer would be tested.

[aysha]

:P hi
Why we set the Proxy setting on Localhost when ever we want to use any testing Tool like e.g WAPT for performance testing and PAROS for security testing, both tool dont work until i set the proxy setting on local host

this is not with these two tool we have to set proxy even for web based application testing as well

what come in my mind is that we set it bcoz specific application or tool can not see the web tracffic until we set its proxy to local host but one thing come in my mind that why we remove already existing IP and why we set it on localhost?
please explain me why we have to do this

Regards!
aysha