title: Interpreting tcpdump output
body: <pre><code>+ 05:09:27.978249 IP 10.0.3.25 &gt; 10.0.4.25: ICMP echo request, id 2604, seq 162, length 64
  + 05:09:27.978281 IP 10.0.4.25 &gt; 10.0.3.25: ICMP echo reply, id 2604, seq 162, length 64
  + 05:09:27.979776 IP 10.0.4.25.45430 &gt; google-public-dns-a.google.com.domain: 14148+ PTR? 25.4.0.10.in-addr.arpa. (40)
  + 05:09:27.981683 IP google-public-dns-a.google.com.domain &gt; 10.0.4.25.45430: 14148 NXDomain 0/0/0 (40)
  + 05:09:27.981841 IP 10.0.4.25.46696 &gt; google-public-dns-a.google.com.domain: 10797+ PTR? 25.3.0.10.in-addr.arpa. (40)
  + 05:09:27.983583 IP google-public-dns-a.google.com.domain &gt; 10.0.4.25.46696: 10797 NXDomain 0/0/0 (40)
  + 05:09:27.983714 IP 10.0.4.25.60389 &gt; google-public-dns-a.google.com.domain: 15771+ PTR? 8.8.8.8.in-addr.arpa. (38)
  + 05:09:27.995332 IP google-public-dns-a.google.com.domain &gt; 10.0.4.25.60389: 15771 1/0/0 PTR google-public-dns-a.google.com. (82)
  + 05:09:28.979778 IP 10.0.3.25 &gt; 10.0.4.25: ICMP echo request, id 2604, seq 163, length 64
  + 05:09:28.979825 IP 10.0.4.25 &gt; 10.0.3.25: ICMP echo reply, id 2604, seq 163, length 64
  + 05:09:29.981257 IP 10.0.3.25 &gt; 10.0.4.25: ICMP echo request, id 2604, seq 164, length 64
  </code></pre>