Consider the following hyperlink:
<a href="http://www.cs.rutgers.edu/∼shklar/">
What HTTP/1.0 request will get submitted by the browser? What HTTP/1.1 request will get submitted by the browser?
Will these requests change if the browser is configured to contact an HTTP proxy? If yes, how?
Answer
While you could use tcpdump to dump the actual network traffic, curl is surely more handy to test the HTTP conversation from the command line.
An HTTP/1.0 request:
curl -v -0 http://www.cs.rutgers.edu/∼shklar/
* About to connect() to www.cs.rutgers.edu port 80 (#0)
* Trying 128.6.4.24...
* connected
* Connected to www.cs.rutgers.edu (128.6.4.24) port 80 (#0)
> GET /∼shklar/ HTTP/1.0
> User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8r zlib/1.2.5
> Host: www.cs.rutgers.edu
> Accept: */*
>
< HTTP/1.1 404 Not Found
< Date: Wed, 31 Oct 2012 17:57:31 GMT
< Server: Apache/1.3.26 (Unix)
< Content-Type: text/html; charset=iso-8859-1
< Connection: close
An HTTP/1.1 request:
curl -v http://www.cs.rutgers.edu/∼shklar/
* About to connect() to www.cs.rutgers.edu port 80 (#0)
* Trying 128.6.4.24...
* connected
* Connected to www.cs.rutgers.edu (128.6.4.24) port 80 (#0)
> GET /∼shklar/ HTTP/1.1
> User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8r zlib/1.2.5
> Host: www.cs.rutgers.edu
> Accept: */*
>
< HTTP/1.1 404 Not Found
< Date: Wed, 31 Oct 2012 17:59:47 GMT
< Server: Apache/1.3.26 (Unix)
< Content-Type: text/html; charset=iso-8859-1
< Transfer-Encoding: chunked
Use the -x (or --proxy) <[protocol://][user@password]proxyhost[:port]> switch to use a proxy and see the results.
More about curl here: http://curl.haxx.se/docs/manpage.html