diff --git a/include/types/server.h b/include/types/server.h
index 45528fa..fa01810 100644
--- a/include/types/server.h
+++ b/include/types/server.h
@@ -135,6 +135,7 @@
 	struct {
 		const char *file;		/* file where the section appears */
 		int line;			/* line where the section appears */
+		struct eb32_node id;		/* place in the tree of used IDs */
 	} conf;					/* config information */
 };