o Fixed the Idle Scan (-sI) so that scanning multiple hosts doesn't

retest the zombie proxy and reinitialize all of the associated data
  at the beginning of each run. [Kris]

The underlying code checking for this and for changing proxies goes all the
way back to r1486 (2002) and presumably before, but lastproxy was never filled
in and so was nonfunctional.

CHANGELOG

@@ -2,6 +2,10 @@
 
 [NOT YET RELEASED]
 
+o Fixed the Idle Scan (-sI) so that scanning multiple hosts doesn't
+  retest the zombie proxy and reinitialize all of the associated data
+  at the beginning of each run. [Kris]
+
 o [NSE] Added jdwp-version.nse, a script from Michael Schierl that
   finds the version of a Java Debug Wire Protocol server.
 

idle_scan.cc

@@ -997,6 +997,7 @@ void idle_scan(Target *target, u16 *portarray, int numports,
   /* If this is the first call,  */
   if (!*lastproxy) {
     initialize_idleproxy(&proxy, proxyName, target->v4hostip(), ports);
+    strncpy(lastproxy, proxyName, sizeof(lastproxy));
   }
 
   starttime = time(NULL);