Index: src/iface.c
===================================================================
--- src/iface.c	(revision 2538)
+++ src/iface.c	(revision 2539)
@@ -61,6 +61,10 @@
 #include <pcap.h>
 #endif
 
+#ifdef SIOCSIFDESCR
+#include <time.h>
+#endif
+
 /*
  * DEFINITIONS
  */
@@ -3872,6 +3876,7 @@ IfaceSetName(Bund b, const char * ifname)
  * %o for local outer ("physical") address of bundle's first link
  * %O for peer outer ("physical") address of bundle's first link
  * %P for peer outer ("physical") port of bundle's first link
+ * %s for last interface description change time, in unixtime (seconds)
  * %S for interface status (DoD/UP/DOWN)
  * %t for type of bundle's first link (pppoe, pptp, l2tp etc.)
  * %u for self auth name (or dash if self auth name not used)
@@ -4031,6 +4036,11 @@ IfaceSetDescr(Bund b, const char * template)
 	    } else {
 		DST_COPY("-");
 	    }
+	    break;
+	  /* timestamp of interface description change */
+	  case 's':
+	    snprintf(buf, sizeof(buf), "%jd", (intmax_t)time(NULL));
+	    DST_COPY(buf);
 	    break;
 	  /* interface status */
 	  case 'S':