Simple varnish config which will cache all responses with a X-Varnish-Age header.

varnish.vcl

import std;

backend default {
        .host = "127.0.0.1";
        .port = "8000";
}

sub vcl_recv {
        return (lookup);

}

sub vcl_fetch {


        if (beresp.http.x-varnish-age) {
                set beresp.ttl = std.duration(beresp.http.x-varnish-age, 60s);

                unset beresp.http.set-cookie;
                unset beresp.http.vary;
                unset beresp.http.x-varnish-age;

                return (deliver);
        }

        return (hit_for_pass);

}