On Tue, Jun 15, 2010 at 3:56 PM, Tapas Mishra <mightydreams@xxxxxxxxx> wrote: > On Tue, Jun 15, 2010 at 8:16 PM, Tom Evans <tevans.uk@xxxxxxxxxxxxxx> wrote: >> >> I dont understand what you are asking? - the reply comes from apache. > I could not understand I am newcomer to apache.I have used Reverse > Proxy and other settings but do not completely understand it. > So trying to understand how apache behaves when it gets a request to > serve a webpage what is happening in background. > >> HTTP_HOST is a variable that holds the value of the http header >> 'Host'. If the browser doesn't send one, it isn't going to have a >> value. > > What is Host in this reply which you are referring to. > Host is a request header sent with HTTP/1.1 requests indicating the host that the user requested. Apache reads that header in and stores it on the request. mod_rewrite makes that variable available to read with the name HTTP_HOST. If the request is a HTTP/1.0 request, no host header is sent, so HTTP_HOST will be empty if examined. I can't explain the HTTP protocol + Apache on a mailing list. Do what I did and read RFC 2616 to understand HTTP, and read "Apache modules with Perl and C" to understand Apache (although it is a little dated now, it has an excellent section on the request life cycle). This may also help: http://stein.cshl.org/~lstein/talks/perl_conference/apache_api/lifecycle.html Tom --------------------------------------------------------------------- The official User-To-User support forum of the Apache HTTP Server Project. See <URL:http://httpd.apache.org/userslist.html> for more info. To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx " from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
|