Varnish 3.x VCL

backend apache {
        .host = "127.0.0.1";
        .port = "8008";
}
acl purge {
        "localhost";
        "127.0.0.1";
}
sub vcl_recv {
        // Strip cookies for static files:
        if (req.url ~ "\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$") {
                unset req.http.Cookie;
                return(lookup);
        }
        // Remove has_js and Google Analytics __* cookies.
        set req.http.Cookie = regsuball(req.http.Cookie, "(^|;\s*)(__[a-z]+|has_js)=[^;]*", "");
        // Remove a ";" prefix, if present.
        set req.http.Cookie = regsub(req.http.Cookie, "^;\s*", "");
        // Remove empty cookies.
        if (req.http.Cookie ~ "^\s*$") {
                unset req.http.Cookie;
        }
        if (req.request == "PURGE") {
                if (!client.ip ~ purge) {
                        error 405 "Not allowed.";
                }
                ban("req.url ~ " + req.url + " && req.http.host == " + req.http.host);
                error 200 "Purged.";
        }
}
sub vcl_hash {
  if (req.http.Cookie) {
    hash_data(req.http.Cookie);
  }
}
sub vcl_fetch {
        // Strip cookies for static files:
        if (req.url ~ "\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|pdf|txt|tar|wav|bmp|rtf|js|flv|swf|html|htm)$") {
                unset beresp.http.set-cookie;
        }
        // Varnish determined the object was not cacheable
        if (!(beresp.ttl > 0s)) {
                set beresp.http.X-Cacheable = "NO:Not Cacheable";
        } elsif(req.http.Cookie ~"(UserID|_session)") {
            // You don't wish to cache content for logged in users
                set beresp.http.X-Cacheable = "NO:Got Session";
                return(hit_for_pass);
        }  elsif ( beresp.http.Cache-Control ~ "private") {
                 // You are respecting the Cache-Control=private header from the backend
                set beresp.http.X-Cacheable = "NO:Cache-Control=private";
                return(hit_for_pass);
        } elsif ( beresp.ttl < 1s ) {
                // You are extending the lifetime of the object artificially
                set beresp.ttl   = 300s;
                set beresp.grace = 300s;
                set beresp.http.X-Cacheable = "YES:Forced";
        }  else {
                // Varnish determined the object was cacheable
                set beresp.http.X-Cacheable = "YES";
        }
        return(deliver);
}