Create Network Namespace with IPv6 connectivity via Hurricane Electric tunnel

ns-ipv6.sh

#!/usr/bin/env bash

set -x                                                                                       
 
if [[ $EUID -ne 0 ]]; then                                                                   
   echo "You must run this script as root."
   exit 1
fi                                                                                           
 
VETH1_IPV6=fd00::1                                                                           
VPEER1_IPV6=fd00::2                                                                          

# Clean up.                                                                                  
ip netns del ns-ipv6 &>/dev/null                                                             
ip li del veth1 &> /dev/null                                                                 

# Create network namespace.                                                                  
ip netns add ns-ipv6                                                                         

# Create veth pair.                                                                          
ip li add name veth1 type veth peer name vpeer1                                              

# Setup veth1 (host).                                                                        
ip -6 addr add ${VETH1_IPV6}/64 dev veth1                                                    
ip li set dev veth1 up                                                                       

# Setup vpeer1 (network namespace).                                                          
ip li set dev vpeer1 netns ns-ipv6                                                           
ip netns exec ns-ipv6 ip li set dev lo up                                                    
ip netns exec ns-ipv6 ip -6 addr add ${VPEER1_IPV6}/64 dev vpeer1                            
ip netns exec ns-ipv6 ip li set vpeer1 up                                                    

# Direct external traffic to VETH1 through VPEER1 (default gw).                              
ip netns exec ns-ipv6 ip -6 route add default dev vpeer1 via ${VETH1_IPV6}                   

# IP Forwarding.                                                                             
sysctl -w net.ipv6.conf.all.forwarding=1                                                     

# Source NAT (he-ipv6 is the name of the SIT tunnel).                                        
ip6tables -t nat --flush                                                                     
ip6tables -t nat -A POSTROUTING -o he-ipv6 -j MASQUERADE

# Get into ns-ipv6.                                                                          
ip netns exec ns-ipv6 /bin/bash --rcfile <(echo "PS1=\"ns-ipv6> \"")