diff --git a/deploy/charts/cert-manager/templates/deployment.yaml b/deploy/charts/cert-manager/templates/deployment.yaml
index 644c1aa3b9e..72e34d60b4c 100644
--- a/deploy/charts/cert-manager/templates/deployment.yaml
+++ b/deploy/charts/cert-manager/templates/deployment.yaml
@@ -85,6 +85,7 @@ spec:
           - --webhook-dns-names={{ include "webhook.fullname" . }},{{ include "webhook.fullname" . }}.{{ .Release.Namespace }},{{ include "webhook.fullname" . }}.{{ .Release.Namespace }}.svc
           ports:
           - containerPort: 9402
+            protocol: TCP
           env:
           - name: POD_NAMESPACE
             valueFrom: