title: what is the disadvantage using hostSNI(*) in traefik TCP route mapping
body: <p>Now I am using <code>HostSNI(</code>*<code>)</code> to mapping the TCP service like <code>mysql\postgresql...</code> in traefik 2.2.1 in Kubernetes cluster v1.18 . beacuse I am in my local machine and did not have a valid certification. This is the config:</p>
  <pre><code>apiVersion: traefik.containo.us/v1alpha1
  kind: IngressRouteTCP
  metadata:
      name: mysql-ingress-tcp-route
      namespace: middleware
  spec:
      entryPoints:
          - mysql
      routes:
          - match: HostSNI(`*`)
            services:
              - name: report-mysqlha
                  port: 3306
  </code></pre>
  <p>is config works fine in my local machine. But I still want to  know the side effect to using
  <code>HostSNI(</code><em><code>)</code> mapping stratege. What is the disadvantege to using <code>HostSNI(</code></em><code>)</code> not a domain name? Is it possible to using a fake domain name in my local machine?</p>