diff --git a/howto/ganeti.md b/howto/ganeti.md
index cb73a37764da5f6faf9ece8f5451c665a2a85567..8f59c2b8ae4086791aa658d48ca077926639f42c 100644
--- a/howto/ganeti.md
+++ b/howto/ganeti.md
@@ -1067,7 +1067,7 @@ address blocks reserved in the cluster.
 
         auto eth1
         iface eth1 inet static
-            address 172.30.130.1
+            address 172.30.130.1/24
 
     This IP must be allocated in the reverse DNS zone file
     (`30.172.in-addr.arpa`) and the `torproject.org` zone file in