title: mininet: Dynamically created Host cannot ping other Hosts, but Host can ping Switch
body: <p>I am trying to dynamically add Hosts and Links after Mininet Startup.
  I am using the py net.addHost,addLink commands.</p>
  
  <p>Using the standard linear,3 Topology</p>
  
  <p>The code is:</p>
  
  <pre><code>py net.addHost('h4')
  py net.addLink(h4,s3)
  py h4.setMAC("00:30:00:00:30:10")
  py h4.configDefault(defaultRoute = h4.defaultIntf())
  </code></pre>
  
  <p>The last statement ensures h4 has a valid IP address.
  On running ifconfig on h4:</p>
  
  <pre><code>mininet&gt; h4 ifconfig
  h4-eth0   Link encap:Ethernet  HWaddr 00:30:00:00:30:10  
            inet addr:10.0.0.4  Bcast:10.255.255.255  Mask:255.0.0.0
            inet6 addr: fe80::230:ff:fe00:3010/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:25 errors:0 dropped:0 overruns:0 frame:0
            TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:4001 (4.0 KB)  TX bytes:1296 (1.2 KB)
  </code></pre>
  
  <p>Pinging h4 from h1 (part of the static topology):</p>
  
  <pre><code>mininet&gt; h1 ping h4
  PING 10.0.0.4 (10.0.0.4) 56(84) bytes of data.
  From 10.0.0.1 icmp_seq=1 Destination Host Unreachable
  From 10.0.0.1 icmp_seq=2 Destination Host Unreachable
  From 10.0.0.1 icmp_seq=3 Destination Host Unreachable
  </code></pre>
  
  <p>Pinging between static topology nodes (h1 and h3):</p>
  
  <pre><code>mininet&gt; h1 ping h3
  PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.
  64 bytes from 10.0.0.3: icmp_seq=1 ttl=64 time=2.14 ms
  64 bytes from 10.0.0.3: icmp_seq=2 ttl=64 time=0.141 ms
  </code></pre>
  
  <p>Any help will be appreciated! </p>