default: deny all, through a folder app of its own

apps/templates/cloudnative-pg-folder.yaml

@@ -0,0 +1,19 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: cloudnative-pg-folder
+  namespace: argocd
+  finalizers:
+  - resources-finalizer.argocd.argoproj.io
+spec:
+  project: default
+  source:
+    repoURL: https://github.com/rubenhensen/k8scd.git
+    targetRevision: HEAD
+    path: cloudnative-pg
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: cnpg-system
+  syncPolicy:
+    automated:
+      selfHeal: true

apps/templates/default-folder.yaml

@@ -0,0 +1,19 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: default-folder
+  namespace: argocd
+  finalizers:
+  - resources-finalizer.argocd.argoproj.io
+spec:
+  project: default
+  source:
+    repoURL: https://github.com/rubenhensen/k8scd.git
+    targetRevision: HEAD
+    path: default
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: default
+  syncPolicy:
+    automated:
+      selfHeal: true

apps/templates/external-secrets-folder.yaml

@@ -0,0 +1,19 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: external-secrets-folder
+  namespace: argocd
+  finalizers:
+  - resources-finalizer.argocd.argoproj.io
+spec:
+  project: default
+  source:
+    repoURL: https://github.com/rubenhensen/k8scd.git
+    targetRevision: HEAD
+    path: external-secrets
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: external-secrets
+  syncPolicy:
+    automated:
+      selfHeal: true

cert-manager/networkpolicy.yaml

@@ -0,0 +1,73 @@
+# cert-manager's three pods reach each other, DNS and the API server (the
+# node, port 16443), and take connections only from each other and the
+# node: the API server calls the webhook from there and the kubelet probes
+# come from there too (10.1.7.64 is the node's Calico VXLAN address,
+# projectcalico.org/IPv4VXLANTunnelAddr). Nothing scrapes the metrics on
+# 9402. The HTTP-01 solver pods run in each Certificate's own namespace
+# (acme-http01-solver in <namespace>/networkpolicy.yaml), not here.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress
+  ingress:
+    - from:
+        - podSelector: {}
+    - from:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+        - ipBlock:
+            cidr: 10.1.7.64/32
+  egress:
+    - to:
+        - podSelector: {}
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+          podSelector:
+            matchLabels:
+              k8s-app: kube-dns
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    - to:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+      ports:
+        - port: 16443
+---
+# The controller talks to Let's Encrypt (443), and before it lets Let's
+# Encrypt check a challenge it fetches http://<host>/.well-known/... itself
+# (80). Every certificate's host has a public address, node001's or the
+# home router's (checked 2026-10-26), so the LAN stays out.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: controller-to-internet
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: cert-manager
+      app.kubernetes.io/component: controller
+  policyTypes:
+    - Egress
+  egress:
+    - to:
+        - ipBlock:
+            cidr: 0.0.0.0/0
+            except:
+              - 10.0.0.0/8
+              - 100.64.0.0/10
+              - 169.254.0.0/16
+              - 172.16.0.0/12
+              - 192.168.0.0/16
+      ports:
+        - port: 80
+        - port: 443

cloudnative-pg/networkpolicy.yaml

@@ -0,0 +1,56 @@
+# The CloudNativePG operator reaches DNS, the API server (the node, port
+# 16443) and the PostgreSQL instances it runs in other namespaces: the
+# instance manager's status port (8000) and PostgreSQL (5432), which the
+# instances' own policies let in (postgres-cnpg in authentik and immich).
+# Besides its own namespace it takes connections only from the node: the
+# API server calls its webhook (9443) from there and the kubelet probes
+# come from there too (10.1.7.64 is the node's Calico VXLAN address,
+# projectcalico.org/IPv4VXLANTunnelAddr). The chart's Application
+# (apps/templates/cloudnativepg-helm.yaml) only installs the chart, so
+# this folder gets an Application of its own, cloudnative-pg-folder.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress
+  ingress:
+    - from:
+        - podSelector: {}
+    - from:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+        - ipBlock:
+            cidr: 10.1.7.64/32
+  egress:
+    - to:
+        - podSelector: {}
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+          podSelector:
+            matchLabels:
+              k8s-app: kube-dns
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    - to:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+      ports:
+        - port: 16443
+    - to:
+        - namespaceSelector: {}
+          podSelector:
+            matchExpressions:
+              - key: cnpg.io/cluster
+                operator: Exists
+      ports:
+        - port: 8000
+        - port: 5432

default/networkpolicy.yaml

@@ -0,0 +1,14 @@
+# Nothing runs in default (2026-10-26: only the kubernetes Service, whose
+# endpoint is the API server on the node, which this doesn't touch). A pod
+# started here, by `kubectl run` or a manifest without a namespace, gets
+# no network at all, instead of reaching the LAN, Vault and every app.
+# Anything that needs a network gets a namespace and a policy of its own.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress

dns/kustomization.yaml

@@ -7,6 +7,7 @@ resources:
   - external-secret.yaml
   - rbac.yaml
   - cronjob.yaml
+  - networkpolicy.yaml
 
 configMapGenerator:
   - name: dns-sync-script

dns/networkpolicy.yaml

@@ -0,0 +1,37 @@
+# The only pod here is the dns-sync Job (a PostSync hook): it installs its
+# Python packages from PyPI and pushes domains/ to TransIP's API, so it
+# reaches DNS and the internet (not the LAN, the API server or other
+# namespaces). Nothing connects to it.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress
+  egress:
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+          podSelector:
+            matchLabels:
+              k8s-app: kube-dns
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    - to:
+        - ipBlock:
+            cidr: 0.0.0.0/0
+            except:
+              - 10.0.0.0/8
+              - 100.64.0.0/10
+              - 169.254.0.0/16
+              - 172.16.0.0/12
+              - 192.168.0.0/16
+      ports:
+        - port: 443

external-secrets/networkpolicy.yaml

@@ -0,0 +1,68 @@
+# External Secrets' three pods reach each other, DNS and the API server
+# (the node, port 16443); the controller also reads Vault
+# (vault-active.vault.svc:8200, which vault/networkpolicy.yaml lets it
+# into). Besides their own namespace they take connections only from the
+# node: the API server calls the webhook from there and the kubelet probes
+# come from there too (10.1.7.64 is the node's Calico VXLAN address,
+# projectcalico.org/IPv4VXLANTunnelAddr). The Password generator behind
+# gatus/backup-check-token needs no network. The chart's Application
+# (apps/templates/external-secrets-helm.yaml) only installs the chart, so
+# this folder gets an Application of its own, external-secrets-folder.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress
+  ingress:
+    - from:
+        - podSelector: {}
+    - from:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+        - ipBlock:
+            cidr: 10.1.7.64/32
+  egress:
+    - to:
+        - podSelector: {}
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+          podSelector:
+            matchLabels:
+              k8s-app: kube-dns
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    - to:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+      ports:
+        - port: 16443
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: controller-to-vault
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: external-secrets
+  policyTypes:
+    - Egress
+  egress:
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: vault
+          podSelector:
+            matchLabels:
+              app.kubernetes.io/name: vault
+      ports:
+        - port: 8200

mariadb-operator/kustomization.yaml

@@ -3,3 +3,4 @@ kind: Kustomization
 resources:
   - operator-crds-helm.yaml
   - operator-helm.yaml
+  - networkpolicy.yaml

mariadb-operator/networkpolicy.yaml

@@ -0,0 +1,54 @@
+# The mariadb-operator's three pods reach each other, DNS and the API
+# server (the node, port 16443); the operator also connects to MariaDB on
+# 3306 for the databases, users and grants it manages (mbgwp's
+# mariadb-from-operator lets it in). Besides their own namespace they take
+# connections only from the node: the API server calls the webhook from
+# there and the kubelet probes come from there too (10.1.7.64 is the node's
+# Calico VXLAN address, projectcalico.org/IPv4VXLANTunnelAddr). This
+# folder's Application deploys into argocd (the operator's own
+# Applications), hence the namespace here.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default
+  namespace: mariadb-system
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress
+  ingress:
+    - from:
+        - podSelector: {}
+    - from:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+        - ipBlock:
+            cidr: 10.1.7.64/32
+  egress:
+    - to:
+        - podSelector: {}
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+          podSelector:
+            matchLabels:
+              k8s-app: kube-dns
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    - to:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+      ports:
+        - port: 16443
+    - to:
+        - namespaceSelector: {}
+          podSelector:
+            matchLabels:
+              app.kubernetes.io/name: mariadb
+      ports:
+        - port: 3306

velero/networkpolicy.yaml

@@ -0,0 +1,52 @@
+# Velero, its node agent, and the pods it starts here (the data movers of
+# each pod volume backup or restore, kopia's maintenance jobs, the chart's
+# CRD upgrade job) reach each other, DNS, the API server (the node, port
+# 16443) and Garage on the NAS (192.168.1.99:3900, nas/garage). The node
+# agent reads volumes through its hostPath mount, not the network. Besides
+# their own namespace they take connections only from the node (kubelet
+# probes; 10.1.7.64 is the node's Calico VXLAN address,
+# projectcalico.org/IPv4VXLANTunnelAddr); nothing scrapes the metrics on
+# 8085. MinIO (the NAS, port 9000) is not allowed: going back to it means
+# adding its port here as well.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+    - Egress
+  ingress:
+    - from:
+        - podSelector: {}
+    - from:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+        - ipBlock:
+            cidr: 10.1.7.64/32
+  egress:
+    - to:
+        - podSelector: {}
+    - to:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+          podSelector:
+            matchLabels:
+              k8s-app: kube-dns
+      ports:
+        - protocol: UDP
+          port: 53
+        - protocol: TCP
+          port: 53
+    - to:
+        - ipBlock:
+            cidr: 192.168.1.204/32
+      ports:
+        - port: 16443
+    - to:
+        - ipBlock:
+            cidr: 192.168.1.99/32
+      ports:
+        - port: 3900