To test Linux for IPv6 networking support, you can use the ping6 command. The ping6 command is a utility that allows you to send an IPv6 echo request to a remote host and receive an IPv6 echo reply.
To test IPv6 networking support using the ping6 command, open a terminal and enter the following command:
ping6 -c 3 ipv6.google.com
Replace ipv6.google.com with the domain name or IPv6 address of the host that you want to test. The -c option specifies the number of echo requests to send.
If the Linux system is able to send and receive IPv6 packets, the ping6 command will display a series of echo replies from the remote host. For example, the output might look something like this:
PING ipv6.google.com(par03s08-in-x0e.1e100.net (2607:f8b0:4003:c07::68)) 56 data bytes 64 bytes from par03s08-in-x0e.1e100.net (2607:f8b0:4003:c07::68): icmp_seq=1 ttl=54 time=23.3 ms 64 bytes from par03s08-in-x0e.1e100.net (2607:f8b0:4003:c07::68): icmp_seq=2 ttl=54 time=23.0 ms 64 bytes from par03s08-in-x0e.1e100.net (2607:f8b0:4003:c07::68): icmp_seq=3 ttl=54 time=23.3 ms --- ipv6.google.com ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2003ms rtt min/avg/max/mdev = 23.035/23.174/23.320/0.140 ms
If the Linux system is not able to send and receive IPv6 packets, the ping6 command will display an error message indicating that the packets were not transmitted or received.
Keep in mind that the ping6 command is just one way to test IPv6 networking support on a Linux system. You can also use other tools, such as traceroute6 or tcpdump, to test IPv6 networking support or diagnose networking issues.