Let's use 2608/tcp for isisd.
diff --git a/doc/install.texi b/doc/install.texi
index 1823e97..e32b9a7 100644
--- a/doc/install.texi
+++ b/doc/install.texi
@@ -262,6 +262,8 @@
 ospfd         2604/tcp		  # OSPFd vty
 bgpd          2605/tcp		  # BGPd vty
 ospf6d        2606/tcp		  # OSPF6d vty
+ospfapi       2607/tcp		  # ospfapi
+isisd         2608/tcp		  # ISISd vty
 @end example
 
 If you use a FreeBSD newer than 2.2.8, the above entries are already
diff --git a/redhat/quagga.spec.in b/redhat/quagga.spec.in
index 319e507..5308cc4 100644
--- a/redhat/quagga.spec.in
+++ b/redhat/quagga.spec.in
@@ -197,6 +197,7 @@
 %if %with_ospfapi
 zebra_spec_add_service ospfapi  2607/tcp "OSPF-API"
 %endif
+zebra_spec_add_service isisd    2608/tcp "ISISd vty"
 
 /sbin/chkconfig --add zebra 
 /sbin/chkconfig --add ripd