feat(mosquitto): restrict LB ingress to the IoT network

mosquitto-iot accepted MQTT from any world source. Over the last 7 days the mosquitto log shows client connections from 10.2.30.0/24 only. The LB is ETP=Local, so the client address reaches the pod. Refs S28-19 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-11-07 11:16:07 +01:00
2 changed files with 14 additions and 9 deletions
@@ -186,8 +186,8 @@ spec:
    matchLabels:
      app.kubernetes.io/name: mosquitto
  ingress:
-    - fromEntities:
-        - world
+    - fromCIDRSet:
+        - cidrGroupRef: net-iot
      toPorts:
        - ports:
            - port: "1883"
@@ -1,6 +1,13 @@
-# Syslog senders reaching the alloy-syslog LB (ETP=Local, client address
-# reaches the pod): network gear on Management, the SLZB coordinators on
-# IoT, and the UDM itself, which sources from its k8s-ingress address.
+# Targeted carve-out: alloy-syslog needs world ingress on the syslog
+# ports specifically. The Service is ETP=Cluster, so external syslog
+# senders (Proxmox, LXC hosts, network gear) hit the LB IP, get DNAT'd
+# to an alloy pod, and get SNAT'd to the receiving node's cilium_host
+# address. Cilium then sees the source as `world-ipv4` identity (the
+# cilium_host IP isn't a known endpoint), NOT `host` — so the broad
+# monitoring CNP's `fromEntities: host` rule doesn't catch it.
+#
+# Scoped via endpointSelector so this only widens ingress on the
+# alloy-syslog pod, not the whole namespace.
 apiVersion: cilium.io/v2
 kind: CiliumNetworkPolicy
 metadata:
@@ -12,10 +19,8 @@ spec:
      app.kubernetes.io/instance: alloy-syslog
      app.kubernetes.io/name: alloy
  ingress:
-    - fromCIDRSet:
-        - cidrGroupRef: net-management
-        - cidrGroupRef: net-iot
-        - cidrGroupRef: net-k8s-ingress
+    - fromEntities:
+        - world
      toPorts:
        - ports:
            - port: "514"