How to setup IPv6 connectivity with your ISP

Introduction
If your ISP offers native IPv6 connectivity the steps required to enable IPv6 are trivial. For completeness, two different procedures are listed below for enabling IPv6 on your system.

Method A: Configuration File
  Open the file  where eth0 represents the network device facing the internet. Add the following line: IPV6INIT=yes  If your ISP provides IPv6 autoconfiguration, add the following additional line: IPV6_AUTOCONF=yes  If you have received your own IPv6 address and gateway, add the following lines to the file: IPV6ADDR= IPV6_DEFAULTGW= 

Method B: NetworkManager

 * 1) Right click on the NetworkManager icon and select Edit Connections....  Alternatively, execute the command.
 * 2) Select the network connection facing the internet and click on 'Edit
 * 3) Select the IPv6 Settings tab
 * 4) If your ISP provides IPv6 autoconfiguration, select the method Automatic
 * 5) If you have received your own IPv6 address, select the method Manual and click the Add button next to the Addresses box to add the IPv6 address provided to you by your ISP.
 * 6) Optional: If your ISP provided an IPv6 address for a DNS server, add the address to the list in the field DNS servers. This step is not required, if no DNS server is provided, the DNS server configured in your IPv4 settings will be used.
 * 7) Complete the configuration tool and activate the newly configured network connection.