diff --git a/lib/dns/win32/libdns.def b/lib/dns/win32/libdns.def
index 4e0b6bd955..30c19f94ab 100644
--- a/lib/dns/win32/libdns.def
+++ b/lib/dns/win32/libdns.def
@@ -1076,6 +1076,7 @@ dst_key_restore
 dst_key_rid
 dst_key_secretsize
 dst_key_setbits
+dst_key_setexternal
 dst_key_setflags
 dst_key_setinactive
 dst_key_setprivateformat