June 1, 2011, Malaysia -- Exactly a week from now on June 8, IPv6 will be tested in about 300 participating organizations in what is dubbed as "World IPv6 Day". If you are planning to take part but not sure what to do or where to start, an article by Network World’s Scott Hogg might help.

Mr. Hogg recommends checking first the website of The Internet Society (ISOC), coordinator of the event, which contains updates on how to prepare and what to do during the event. The site also has the list of participants that will be operating over IPv6 all day. As early as now, see if you can connect to their websites.

There are also several test sites you can use to verify your Internet connectivity. Mr. Hogg also recommends using the sample C code created by InfoWeapons CTO, Lawrence Hughes, which makes a client perform aggressively to establish IPv4 or IPv6 connection to a server.

Called "non-blocking sockets", Mr. Hughes' technique enables a client to simultaneously try to connect to both the IPv4 and IPv6 addresses of a server. If both connections are successful, the IPv6 connection will be preferred and the IPv4 connection will be quickly disconnected.

Finally, Mr. Hogg suggests checking your firewall if it's handling IPv6 traffic correctly, especially if you are relying on tunnels for IPv6 connectivity. The firewall, he says, should Permit IPv4 protocol 41 (IPv6-in-IPv4 tunneled traffic) and Permit IPv4/UDP port 3544 packets (Teredo).

He adds, "You will want to be cognizant of how tunneling one protocol inside another protocol reduces the effective Maximum Transmission Unit (MTU) size of the encapsulated protocol. For example, if you are using an 6-in-4 tunnel and the IPv4 MTU size if 1500 bytes then the MTU size for IPv6 will be 1480 bytes (1500 bytes less the 20-byte IPv4 header)."

"If you want to learn more about IPv6, Lawrence Hughes has written a great book on IPv6 and graciously provided it to the world free of charge," says Mr. Hogg.

Mr. Hughes' book, "The Second Internet: Reinventing Computer Networks with IPv6", is free to download here.

Source: Network World