diff --git a/socks/main.go b/socks/main.go
index 171b5fc13..6cde493d3 100644
--- a/socks/main.go
+++ b/socks/main.go
@@ -13,13 +13,18 @@ import (
 	"github.com/weaveworks/weave/common/mflagext"
 )
 
+type pacFileParameters struct {
+	HostMatch string
+	Aliases   map[string]string
+}
+
 const (
 	pacfile = `
 function FindProxyForURL(url, host) {
-	if(shExpMatch(host, "*.weave.local")) {
+	if(shExpMatch(host, "{{.HostMatch}}")) {
 		return "SOCKS5 localhost:8000";
 	}
-	{{range $key, $value := .}}
+	{{range $key, $value := .Aliases}}
 	if (host == "{{$key}}") {
 		return "SOCKS5 localhost:8000";
 	}
@@ -30,8 +35,12 @@ function FindProxyForURL(url, host) {
 )
 
 func main() {
-	var as []string
+	var (
+		as        []string
+		hostMatch string
+	)
 	mflagext.ListVar(&as, []string{"a", "-alias"}, []string{}, "Specify hostname aliases in the form alias:hostname.  Can be repeated.")
+	mflag.StringVar(&hostMatch, []string{"h", "-host-match"}, "*.weave.local", "Specify main host shExpMatch expression in pacfile")
 	mflag.Parse()
 
 	var aliases = map[string]string{}
@@ -50,7 +59,7 @@ func main() {
 	t := template.Must(template.New("pacfile").Parse(pacfile))
 	http.HandleFunc("/proxy.pac", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/x-ns-proxy-autoconfig")
-		t.Execute(w, aliases)
+		t.Execute(w, pacFileParameters{hostMatch, aliases})
 	})
 
 	if err := http.ListenAndServe(":8080", nil); err != nil {