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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-CA">We use Varnish to cache for multiple backends and need Varnish to
<b>always</b> control what is cached despite what backends could respond. In other words, even if a backend sets Cache-Control headers to never cache its pages, we still want Varnish to cache them based on defined rules (i.e. certain URL patterns or hosts have
different TTLs).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">We have recently realized that one of our backend always set the following header:
<b>Cache-Control: max-age=0, private, must-revalidate</b><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Our VCL unsets the Cache-Control header in vcl_backend_response and sets its own before delivering. By unsetting the Cache-Control header in vcl_backend_response I would expect Varnish to ignore the max-age=0 value and
still cache the page as per our other rules, but it seems that the second it sees max-age=<b>0
</b>in the response header, that it makrs the object as not cacheable.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Other than by changing the backend's response to never set max-age=0, is there a way to force Varnish to cach pages even if it returned max-age=0?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Is this even by design or is it a bug?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA">Thanks, <o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-CA" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#4F5150;mso-fareast-language:FR-CA">Yanick Girouard</span></b><span lang="EN-CA" style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#4F5150;mso-fareast-language:FR-CA"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-CA"><o:p> </o:p></span></p>
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