Ensure next_uid() can never return 0.
diff --git a/src/cache.c b/src/cache.c
index a7be5f1..a3f9c3a 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -74,13 +74,15 @@
 
 static unsigned int next_uid(void)
 {
-  static unsigned int uid = 1;
+  static unsigned int uid = 0;
 
+  uid++;
+  
   /* uid == 0 used to indicate CNAME to interface name. */
   if (uid == 0)
     uid++;
   
-  return uid++;
+  return uid;
 }
 
 void cache_init(void)