That header is probably set by a caching layer (e.g. Varnish). You can get a similar effect by using the Boost module, which would bypass Drupal and have the cached pages served directly by Apache from static files (assuming you are using that web server). There are other caching solutions, of course, YMMV.

Ted

On 8/29/2013 1:03 PM, Shérab wrote:

Dear all,

I noticed that on my D6 Drupal site's home page, the Content-Length HTTP header is not defined. I thought it is perhaps not possible to compute it for dynamically generated content, butIcheckedon drupal.org's home page and it has the header. Any idea howI can do to have it?

Thanks, Sherab.