title: Meaning of SS command output with 3 colons (':::')?
body: <p>The increasingly popular ss command (/usr/sbin/ss on RHEL) is a replacement for netstat.</p>
  
  <p>I'm trying to parse the output in Python and I'm seeing some odd data that is not explained in the documentation.</p>
  
  <pre><code>$ ss -an | head
  State    Recv-Q Send-Q    Local Address:Port      Peer Address:Port
  LISTEN   0      0                    :::14144               :::*
  LISTEN   0      0             127.0.0.1:32000                *:*
  LISTEN   0      0                    :::3233                :::*
  LISTEN   0      0                     *:5634                 *:*
  LISTEN   0      0                    :::5634                :::*
  </code></pre>
  
  <p>So, it's obvious what the local address means when it's 127.0.0.1:32000, obviously listening on the loopback interface on port 32000. But, what do the 3 colons ::: mean?  </p>
  
  <p>Really, I can figure it's two extra colons, since the format is host:port, so <strong>what does a host of two colons mean?</strong></p>
  
  <p>I should mention I'm running this on a RHEL/CENTOS box:</p>
  
  <pre><code>Linux boxname 2.6.18-348.3.1.el5 #1 SMP somedate x86_64 x86_64 x86_64 GNU/Linux
  </code></pre>
  
  <p>This is not explained in <strong>any</strong> of the online man pages or other discussions I can find.</p>