diff --git a/config.h.in b/config.h.in
index fe410b218c953d307be431300256f7383dd84e50..4e86c9d2ab5dc61d700e6f44864d03869fd69954 100644
--- a/config.h.in
+++ b/config.h.in
@@ -173,9 +173,6 @@ int sigwait(const unsigned int *set, int *sig);
 /* Define to enable rpz-nsip rules. */
 #undef ENABLE_RPZ_NSIP
 
-/* Define to enable 'sit' support. */
-#undef ENABLE_SIT
-
 /* Solaris hack to get select_large_fdset. */
 #undef FD_SETSIZE
 
diff --git a/configure b/configure
index 281913e1e14ebf34852d920ba54fb78d40b4f06c..54c1c7c2626c5afa5801bb933fe5b50a15b2c1a6 100755
--- a/configure
+++ b/configure
@@ -19064,9 +19064,6 @@ HAVE_SIT=
 
 case "$enable_sit" in
 yes)
-
-$as_echo "#define ENABLE_SIT 1" >>confdefs.h
-
 	ISC_PLATFORM_USESIT="#define ISC_PLATFORM_USESIT 1"
         HAVE_SIT=1
 	;;
diff --git a/configure.in b/configure.in
index 60d85da68d4dc2787740170b30b10934891aceac..e5a030d7f06752091b95214c1ecdf40d79b5c232 100644
--- a/configure.in
+++ b/configure.in
@@ -3448,7 +3448,6 @@ HAVE_SIT=
 
 case "$enable_sit" in
 yes)
-	AC_DEFINE(ENABLE_SIT, 1, [Define to enable 'sit' support.])
 	ISC_PLATFORM_USESIT="#define ISC_PLATFORM_USESIT 1"
         HAVE_SIT=1
 	;;