diff --git a/nest/config.Y b/nest/config.Y
new file mode 100644
index 00000000..f14331b3
--- /dev/null
+++ b/nest/config.Y
@@ -0,0 +1,32 @@
+/*
+ *	BIRD -- Core Configuration
+ *
+ *	(c) 1998 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+CF_HDR
+
+CF_DECLS
+
+CF_KEYWORDS(ROUTER, ID)
+
+%type <i> idval
+
+CF_GRAMMAR
+
+CF_ADDTO(conf, rtrid)
+rtrid: ROUTER ID idval {
+   router_id = $3;
+ }
+ ;
+
+idval:
+   NUM
+ | IPA { $$ = ipa_to_u32($1); }
+ ;
+
+CF_CODE
+
+CF_END