title: What is the default action for an SPF record if 'all' is absent?
body: <p>If I have an SPF record like:</p>
  
  <pre><code>v=spf1 +a a:spf2.example.com ip4:104.130.122.xxx/23
  </code></pre>
  
  <p>What is the default policy for sources not mentioned in the record if the final <code>all</code> parameter is omitted?</p>