diff --git a/src/include/gpxe/in.h b/src/include/gpxe/in.h
index 5ae66769..2581eda5 100644
--- a/src/include/gpxe/in.h
+++ b/src/include/gpxe/in.h
@@ -29,5 +29,6 @@ struct sockaddr_in {
 };
 
 extern int inet_aton ( const char *cp, struct in_addr *inp );
+extern char * inet_ntoa ( struct in_addr in );
 
 #endif	/* _IN_H */