diff --git a/main.go b/main.go
index a813738..a37ba54 100644
--- a/main.go
+++ b/main.go
@@ -102,6 +102,21 @@ func octetsRaw(ip string) ([]string, error) {
 	return parts, nil
 }
 
+func getenv(k, d string) string {
+	if v := os.Getenv(k); v != "" {
+		return v
+	}
+	return d
+}
+
+func enabled(k string, def bool) bool {
+	b, err := strconv.ParseBool(strings.ToLower(os.Getenv(k)))
+	if err != nil {
+		return def
+	}
+	return b
+}
+
 func DhcpHelperFunc(xHostname string, xDUIDs []string, xIAIDs []uint32) []payloadHelper {
 	/*IPv4*/
 	Ipv4Octets, _ := octetsRaw(defaultIP)
@@ -317,7 +332,7 @@ func uint32ToIP(u uint32) net.IP {
 // ---------------------------------------------------------------------------
 func initConfigAndTemplates() {
 	// ULA prefix ---------------------------------
-	ulaPrefix = os.Getenv("ULA_PREFIX")
+	ulaPrefix = getenv("ULA_PREFIX", "fd12:3456:789A:BCDE::")
 	if ulaPrefix == "" {
 		ulaPrefix = defaultPrefix
 	}
@@ -330,8 +345,8 @@ func initConfigAndTemplates() {
 	}
 
 	// DNS defaults --------------------------------
-	dns1 = os.Getenv("DNS1")
-	dns2 = os.Getenv("DNS2")
+	dns1 = getenv("DNS1", "fd12:3456:789A:BCDE::ac10:a")
+	dns2 = getenv("DNS2", "fd12:3456:789A:BCDE::ac10:b")
 	if dns1 == "" {
 		dns1 = strings.Replace(ulaPrefix, "::", "::53", 1)
 	}
@@ -340,7 +355,7 @@ func initConfigAndTemplates() {
 	}
 
 	// Placeholder IP ------------------------------
-	pageIP = os.Getenv("FORM_DEFAULT_IP")
+	pageIP = getenv("FORM_DEFAULT_IP", "172.16.0.0")
 	if pageIP == "" {
 		pageIP = defaultIP
 	}