Installer: mail-gateway configure downstream smtp server addresses
diff --git a/charts/mail-gateway/templates/mx-certificate.yaml b/charts/mail-gateway/templates/mx-certificate.yaml
new file mode 100644
index 0000000..c4012ae
--- /dev/null
+++ b/charts/mail-gateway/templates/mx-certificate.yaml
@@ -0,0 +1,14 @@
+apiVersion: cert-manager.io/v1
+kind: Certificate
+metadata:
+  name: {{ .Values.domains.primary.mx }}
+  namespace: {{ .Release.Namespace }}
+  annotations:
+    "helm.sh/resource-policy": keep
+spec:
+  dnsNames:
+  - {{ .Values.domains.primary.mx }}
+  issuerRef:
+    name: {{ .Values.domains.primary.certificateIssuer }}
+    kind: ClusterIssuer
+  secretName: cert-{{ .Values.domains.primary.mx }}