doc: add initial nhrpd documentation
diff --git a/doc/install.texi b/doc/install.texi
index 811ad9a..4ad282a 100644
--- a/doc/install.texi
+++ b/doc/install.texi
@@ -283,6 +283,7 @@
 ospfapi       2607/tcp		  # ospfapi
 isisd         2608/tcp		  # ISISd vty
 pimd          2611/tcp		  # PIMd vty
+nhrpd         2612/tcp		  # nhrpd vty
 @end example
 
 If you use a FreeBSD newer than 2.2.8, the above entries are already