diff --git a/conf/sip_profiles/internal.xml b/conf/sip_profiles/internal.xml
index af78c6644a..05cd9c870b 100644
--- a/conf/sip_profiles/internal.xml
+++ b/conf/sip_profiles/internal.xml
@@ -53,7 +53,7 @@
     <!-- ip address to bind to, DO NOT USE HOSTNAMES ONLY IP ADDRESSES -->
     <param name="sip-ip" value="$${local_ip_v4}"/>
     <param name="hold-music" value="$${hold_music}"/>
-    <param name="apply-nat-acl" value="rfc1918"/>
+    <param name="apply-nat-acl" value="rfc1918.auto"/>
     <!--<param name="aggressive-nat-detection" value="true"/>-->
     <!--<param name="enable-100rel" value="true"/>-->
     <!--<param name="minimum-session-expires" value="120"/>-->