diff --git a/acconfig.h b/acconfig.h
index 78d2e9b827..8b37b5b8db 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -17,9 +17,6 @@
  ***/
 @TOP@
 
-/** define if you have the NET_RT_IFLIST sysctl variable and sys/sysctl.h */
-#undef HAVE_IFLIST_SYSCTL
-
 /** define if tzset() is available */
 #undef HAVE_TZSET
 
diff --git a/config.h.in b/config.h.in
index a768eeccb6..d4673ead18 100644
--- a/config.h.in
+++ b/config.h.in
@@ -17,9 +17,6 @@
  *** it does not get installed.
  ***/
 
-/** define if you have the NET_RT_IFLIST sysctl variable and sys/sysctl.h */
-#undef HAVE_IFLIST_SYSCTL
-
 /** define if tzset() is available */
 #undef HAVE_TZSET
 
diff --git a/config.h.win32 b/config.h.win32
index 15d42b928b..4f19200b1d 100644
--- a/config.h.win32
+++ b/config.h.win32
@@ -76,9 +76,6 @@
 /* define if catgets() is available */
 /* #undef HAVE_CATGETS */
 
-/* define if you have the NET_RT_IFLIST sysctl variable. */
-#define HAVE_IFLIST_SYSCTL 1
-
 /* define if you need to #define _XPG4_2 before including sys/socket.h */
 /* #undef NEED_XPG4_2_BEFORE_SOCKET_H */