mg_server_cache.vcl

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

sub vcl_recv {
   if (req.request != "GET"
    && req.request != "HEAD") {
       return (pass);
   }

   if (req.http.if-none-match == "%22cacheme%22") {
       error 304 "Not Modified";
   }

   call normalize_compression;
   # call normalize_request;

   return (lookup);
}

# sub normalize_request {
   # if (req.url !~ "^/f/"
   #  && req.url !~ "^/l10n/" ) {
   #     set req.http.host = "img.blah.blah";
   # }

   # no signature
   # /f/spot/: homepage top5
   # /f/tiny/: thumbnails adv page
   # /f/markt\d/: lijstuitvoer

   # signature
   # /f/preview/: main pics big adv page
   # /f/normal/: lytebox main pics adv page
# } 

sub normalize_compression {
   # normalize compression, prefer gzip
   if (req.http.Accept-Encoding) {
       if (req.url ~ "\.(ico|jpe?g|png|gif|gz|tgz|bz2|tbz|mp3|ogg|zip|rar|r\d\d|ace)$") {
           # no point in compressing these
           remove req.http.Accept-Encoding;
       } elsif (req.http.Accept-Encoding ~ "gzip") {
           set req.http.Accept-Encoding = "gzip";
       } elsif (req.http.Accept-Encoding ~ "deflate") {
           set req.http.Accept-Encoding = "deflate";
       } else {
           # unkown algorithm
           remove req.http.Accept-Encoding;
       }
   }
}

sub vcl_fetch {
   if (obj.cacheable) {
       unset obj.http.set-cookie;
       set obj.http.etag = "%22cacheme%22";

       return (deliver);
   } else {
       return (pass);
   }
}

sub vcl_error {
   if (obj.status == 304) {
       set obj.http.X-Varnish = "304 Not Modified";
       deliver;
   }
}

varnish_config.sh

#!/bin/sh
echo starting varnish daemon
/usr/local/varnish-2.0.6/sbin/varnishd \
  -s malloc,3G \
  -a 0.0.0.0:7999 \
  -p sess_timeout=3 \
  -p thread_pool_min=200 \
  -p thread_pool_max=4000 \
  -p thread_pools=4 \
  -p listen_depth=1024 \
  -p lru_interval=5 \
  -p obj_workspace=4096 \
  -f /home/blah/blah/setup/varnish/img_server_cache.vcl
echo done