How to make Varnish not caching response if they do not have proper cache header?

Question

Seems Varnish is caching too aggressively, e.g. I have a index.php does not send out last-modifieid, cache-control, Varnish still cache it.

my default.vcl

backend default {
    .host = "127.0.0.1";
    .port = "8080";
}

Is it possible to turn off this strange behaviors?

Answer 1

Varnish by default will cache as much as possible - to the TTL (Time To Live) it was set when it's daemon was started.

If your index.php doesn't send Cache-Control headers, varnish will try to cache it, unless that page sends (or recieves) a cookie from the user.

You can control exactly what varnish is doing (to an extremely fine degree) using Varnish Control Language; normally putting things in 'vcl_recv' and 'vcl_fetch'.

The varnish wiki is very good, have a look at the config examples. Also, you can find tonns of stuff by googling it!

https://www.varnish-cache.org/trac/wiki/VCL

https://www.varnish-cache.org/trac/wiki/VCLExamples