Index: channels/iax2.h
===================================================================
--- channels/iax2.h	(revision 30722)
+++ channels/iax2.h	(working copy)
@@ -69,7 +69,9 @@
 #define IAX_COMMAND_FWDATA	37	/* Firmware Data */
 #define IAX_COMMAND_TXMEDIA 38  /* Transfer media only */
 
-#define IAX_DEFAULT_REG_EXPIRE  60	/* By default require re-registration once per minute */
+#define IAX_DEFAULT_REG_EXPIRE  45  /* By default require re-registration once every 45 seconds. */
+                                    /* It should be less than 60 seconds to avoid UDP port */
+                                    /* translation timeouts in certain firewall appliances. */
 
 #define IAX_LINGER_TIMEOUT		10 /* How long to wait before closing bridged call */