title: How to capture packages via both eth0 and lo at the same time?
body: <p>There are two net interfaces on my pc.</p>
  
  <pre><code>netstat -i
  Kernel Interface table
  Iface   MTU Met   RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
  eth0       1500 0     27186      0      0 0         20784      0      0      0 BMRU
  lo        65536 0     42025      0      0 0         42025      0      0      0 LRU
  </code></pre>
  
  <p>Packages via lo can captured by.</p>
  
  <pre><code>sudo tcpdump  -i lo 
  </code></pre>
  
  <p>Packages via eth0 can captured by.</p>
  
  <pre><code>sudo tcpdump  -i eth0 
  </code></pre>
  
  <p>How to capture packages via both eth0 and lo at the same time?<br>
  <strong>sudo tcpdump  -i eth0 -i lo</strong> can not work.<br>
  <strong>sudo tcpdump  -i eth0 -i lo</strong> = <strong>sudo tcpdump  -i eth0</strong>=<strong>sudo tcpdump</strong></p>