Accessing the default network namespace

If there are no network interfaces configured in the default (root) network namespace, we can't get to that network namespace via ssh, and we can't switch to it using the ip netns exec <network_namespace> command since the default network namespace has no name.

A workaround is to do the following:

1. create a name for the default network namespace, e.g. 'default'

   sudo ln -s /proc/1/ns/net /var/run/netns/default

   now it shows up in the list of network namespaces:

   pi@netperf:~ $ ip netns
   default
   ns_wlan0
   ns_enxb827eb16f253
   bwmonitor
   

2. now we can switch to the default network namespace:

   sudo ip netns exec default sudo -H -u pi bash

   view the network namespace our shell is now in:

   ip netns identify $$

   The output should be an empty line; this means that we're in the default (root) network namespace.