On a site where a contact form is displayed at the bottom of each page, I implemented Varnish caching. To do so I had to deactivate Recaptcha to avoid 'no cache -must revalidate " headers.
I tried other antispam solutions such as Honeypot or Botcha, but Honeypot is not efficient (at least with time limit disabled), and Botcha also invalidates cache. I'd really prefer to go on with Recaptcha
Did anybody could make Recaptcha work with Varnish ?