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    <head>
      <base href="https://bugzilla.netfilter.org/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - can not reuse source port to a DNATed IP if it is being used by another connection"
   href="https://bugzilla.netfilter.org/show_bug.cgi?id=1427">1427</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>can not reuse source port to a DNATed IP if it is being used by another connection
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>netfilter/iptables
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86_64
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P5
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>NAT
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>netfilter-buglog@lists.netfilter.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>antonio.ojea.garcia@gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Scenario:

There is one established connection IP1:Port1 -> IP2:Port2
There is a DNAT rule like IP3:Port3 -> IP2:Port2

If a new connection is created from IP1 to IP3:Port3,
and this connection has source port Port1,
the connection can not be established,
because the incoming packet is not de-natted

The bug was originally reported in Kubernetes:
<a href="https://github.com/kubernetes/kubernetes/issues/90258">https://github.com/kubernetes/kubernetes/issues/90258</a>

but I was able to reproduce it here:
<a href="https://gist.github.com/aojea/4ffb520db9f72de21685294d8fec7f33">https://gist.github.com/aojea/4ffb520db9f72de21685294d8fec7f33</a></pre>
        </div>
      </p>
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