diff --git a/m/bay/configuration.nix b/m/bay/configuration.nix
index 7bdfe740..9bb353eb 100644
--- a/m/bay/configuration.nix
+++ b/m/bay/configuration.nix
@@ -35,7 +35,7 @@
         # Accept monitoring requests from hut
         iptables -A nixos-fw -p tcp -s hut -m multiport --dport 9283,9002 -j nixos-fw-accept
         # Accept all Ceph traffic from the local network
-        iptables -A nixos-fw -p tcp -s 10.0.40.0/24 -m multiport --dport 3300,6789,6800:7568 -j nixos-fw-accept
+        iptables -A nixos-fw -p tcp -s 10.0.40.0/21 -m multiport --dport 3300,6789,6800:7568 -j nixos-fw-accept
       '';
     };
   };
diff --git a/m/lake2/configuration.nix b/m/lake2/configuration.nix
index 477cf59c..338c2d40 100644
--- a/m/lake2/configuration.nix
+++ b/m/lake2/configuration.nix
@@ -57,7 +57,7 @@
         # Accept monitoring requests from hut
         iptables -A nixos-fw -p tcp -s hut --dport 9002 -j nixos-fw-accept
         # Accept all Ceph traffic from the local network
-        iptables -A nixos-fw -p tcp -s 10.0.40.0/24 -m multiport --dport 3300,6789,6800:7568 -j nixos-fw-accept
+        iptables -A nixos-fw -p tcp -s 10.0.40.0/21 -m multiport --dport 3300,6789,6800:7568 -j nixos-fw-accept
       '';
     };
   };