2607/tcp is already used by ospfapi.
Let's use 2608/tcp for isisd.
diff --git a/SERVICES b/SERVICES
index d74098f..9c3546b 100644
--- a/SERVICES
+++ b/SERVICES
@@ -15,4 +15,5 @@
ospfd 2604/tcp
bgpd 2605/tcp
ospf6d 2606/tcp
-isisd 2607/tcp
+ospfapi 2607/tcp
+isisd 2608/tcp
diff --git a/isisd/isis_main.c b/isisd/isis_main.c
index 8106492..5681350 100644
--- a/isisd/isis_main.c
+++ b/isisd/isis_main.c
@@ -47,7 +47,7 @@
/* Default configuration file name */
#define ISISD_DEFAULT_CONFIG "isisd.conf"
/* Default vty port */
-#define ISISD_VTY_PORT 2607
+#define ISISD_VTY_PORT 2608
/* isisd privileges */
zebra_capabilities_t _caps_p [] =