World IPv6 Day (June 8, 2011) is approaching in about a week. This will be a landmark day for IPv6 Internet connectivity and IPv6-capable content providers. You will want to be prepared for this historic day in networking. This article will give you the background on what is happening on that day and how to help your organization be ready for the fun. You may have already heard of World IPv6 Day. The initial announcement came on January 12th of this year. As more organizations realized that this was a good idea, others joined in by making announcements of their intent to participate. Over the past few months there has been more coverage of the event. This quarter's The Internet Protocol Journal (Volume 14, Number 1) has an article on World IPv6 Day and its contents are almost completely IPv6-related. World IPv6 Day is even listed in this month's WIRED magazine as the "Nerdiest Holiday Ever: 6/8/11" (June 2011 on page 50). Even though their article was devoid of any good technical substance it was nevertheless amusing. Their suggestions for how to prepare and celebrate the day include: bake a cake, decorate your office in orange streamers, give gifts, and send a card. I decided to take their advice and make a greeting card to commemorate the day. However, giving a gift of a static public IPv4 address would also be a nice present. :^)
The technical issue that is prompting World IPv6 Day is this concept known as "IPv6 Brokenness". There is a small population of the Internet that has incomplete IPv6 connectivity. Essentially, there could be holes in the IPv6 connectivity for some people that prevents them from having end-to-end IPv6 reachability. These organizations who have broken IPv6 connectivity may not even realize they have a problem because the vast majority of Internet content is reachable with IPv4. The broken end-to-end IPv6 connectivity can be caused by incomplete deployment of IPv6 or broken tunnels or operating systems and applications that do not behave correctly. If an organization has broken IPv6 connectivity, then those users will experience a delay in reaching a dual-protocol web site. Based on their web browser and their operating system, this timeout can be just a few seconds to several minutes, as their browser tries to reach the site's IPv6 address, fails, then falls back to the IPv4 address.
Today, many companies who are concerned about this "IPv6 Brokenness" maintain two different URLs; one is for an IPv4-only site and one is for an IPv6-only site. For example, Cisco has http://www.cisco.com which is their IPv4-only site and http://www.ipv6.cisco.com/ which is their IPv6-only site. Large Internet content providers are fearful of the IPv6 Brokenness causing hundreds of thousands of Internet users not being able to reach their sites. These companies would prefer to have a single web site URL function for both IPv4 and IPv6 and have a single brand-name regardless of client IP version.
On World IPv6 Day, companies like Cisco will make their primary web site function for both IPv4 and IPv6. To do this, they will change their DNS zone files to have the same hostname associated with both an A record and an AAAA record (Quad-A). Their web servers will then be configured for dual-stack operation and service TCP port 80 connections on both its IPv4 address and its IPv6 address. If an organization was using BIND, then their forward lookup zone file would look something like this.
www IN A 192.168.1.101
www IN AAAA 2001:db8:1::101
During World IPv6 Day these content providers will have the same content be available with the same URL over IPv4 and IPv6 transport.
There have been several organizations who already publish an A record and an AAAA record in their authoritative DNS for the primary web site. The Rocky Mountain IPv6 Task Force (RMv6TF) has always had a dual-protocol site. This is easy to establish when you use Hurricane Electric (HE) for your hosting provider. HE has embraced IPv6 for many years and "Every day is World IPv6 Day at Hurricane Electric". Other organizations like the German news site Heise and two websites in Norway (A-pressen Digitale Medier and VG Multimedia) have held similar World IPv6 Tests in 2010. The Galve Sweden Christmas Goat tradition web-cam traffic analysis has also helped analyze the impact of having dual-protocol content on the Internet.
The events taking place on World IPv6 Day are being coordinated by the Internet Society (ISOC). They have a page that describes what is happening on that day. This will be a key web site to check in with prior to June 8th to learn important information and updates on the event. ISOC is maintaining a list of participants in World IPv6 Day. There are now almost 300 organizations participating. On that day you can go visit these web sites and validate that your organization can reach these sites.
It is also important to remember that the world is round and has many time zones. World IPv6 Day begins at 00:00 UTC and goes until 23:59 UTC. Therefore, if you live in North America World IPv6 Day will actually start the evening of June 7th. I live in Denver Colorado, so I will start World IPv6 day at 6PM on June 7th and it will last until 6PM June 8th.
You may be wondering how you prepare for World IPv6 Day. You may be wondering if you need to go stockpile provisions for your underground bunker. World IPv6 Day is not one of those "the end of the world, as we know it" (TEOTWAWKI) prophecies of doom and gloom. However, if you are not prepared you may be doing a lot of troubleshooting and explaining to your users and downstream customers what IPv6 is and why they can't rapidly reach these major content providers web sites. If you aren't prepared then you may end up working 24 hours that day be glad when World IPv6 Day ends.
One of the ways to prepare is to follow the guidance that ISOC provides on their web site. If you are a web site owner and want to actively participate in the festivities, or if you operate a network and want to make sure there is minimal disruption for your end users, here is a link for you. If you are interested in joining the party, you can visit the ISOC page and have your organization be listed as a participant.
One method of verifying if you are ready for IPv6 day is to browse to a test web site. This experiment will verify if you have IPv4 and/or IPv6 Internet connectivity and if your DNS, client operating system, and web browser are having any problems that could cause you problems on World IPv6 Day. You can browse to this site and validate that everything is working well from the perspective of your end-users.
Lawrence Hughes, CTO of InfoWeapons has created some code in C that will make a client perform aggressively and simultaneously connect to both the IPv4 address and the IPv6 address of server. This technique is called "non-blocking sockets". Once the connection is made using one of these addresses then the other connection is disconnected. However, if both connections are successful then the IPv6 connection will continue to operate and the IPv4 connection will be torn down. Lawrence has set up sites v4address.com and v6address.com that you can test with using his telar application This is a similar approach to the IETF draft "Happy Eyeballs" which documents how clients should be aggressive about connecting with IPv4 and IPv6 and even TCP and SCTP simultaneously, preferring IPv6 and SCTP, and then disconnecting the other connections. 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.
In order to prepare to participate in World IPv6 Day you may want to make sure that our firewalls are handling IPv6 traffic correctly. If you already have IPv6 deployed then you will want to test your IPv6 Internet connectivity extensively. If you are relying on tunnels for IPv6 connectivity then you will want to verify that your firewalls Permit IPv4 protocol 41 (IPv6-in-IPv4 tunneled traffic) and Permit IPv4/UDP port 3544 packets (Teredo). 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).
You will also want to test your DNS infrastructure for its capability to serve and resolve IPv6 addresses using IPv4 and/or IPv6 transport. While you are at it you may want to check that your firewall can allow inbound and outbound DNS queries using TCP and UDP port 53. You will also want to verify that your firewall will allow UDP DNS queries larger than the 512 byte limit. You can refer by my previous blog about how to check and configure EDNS0.
Other companies are also helping organizations prepare for World IPv6 Day. Internet Service Providers (ISPs) have been working for years on their IPv6 connectivity services. Collocation and hosting providers have also been working on their IPv6 services to their customers. OpenDNS now offers support for IPv6 to help their customers actively participate in World IPv6 Day. Nominum is also preparing for World IPv6 Day with its IPv6 Readiness Program to provide organizations access to their IPv6-capable DNS and DHCPv6 software for testing purposes.
One important thing you can do to get ready is to notify your helpdesk of World IPv6 Day and the issues that are likely to arise on that day. It will be beneficial to document any issues with Internet connectivity and troubleshoot those problems. You will want to make sure you can troubleshoot end-to-end connectivity problems with IPv4 or IPv6 and test DNS resolution issues that might affect IPv4 or IPv6. You will want to leverage your troubleshooting procedures to quickly determine the root cause of any problems your users are experiencing reaching these major content provider's web sites. You can refer your operations teams to read my previous blog post on "Troubleshooting IPv6 Networks and Systems". This should help you troubleshoot problems that you may encounter on World IPv6 Day.
Whatever you do, you should not disable IPv6. I actually cringe every time I hear some say "if you are having problems ... just disable IPv6". In most of the modern operating systems, IPv6 is enabled and pre-configured as the preferred protocol. IPv6 cannot really be completely disabled in the operating system anyway. Disabling IPv6 on interfaces will have other undesirable consequences. Operationally it would be too difficult to disable IPv6 across an entire organization and in the near future you will absolutely want it turned on for all your end-users. Disabling IPv6 will just cause you more hassles in the not-so-distant future.
Google was one of the first organizations to announce its intentions to participate in the World IPv6 Day activities. Since then, Google has been preparing for World IPv6 Day. Google has updated Chrome 11 to have an IPv4-fallback feature so that if IPv6 connectivity fails the browser will try making an IPv4 connection faster. The browser will also set a race between the two protocols and see which one wins. If both IPv4 and IPv6 connect then the preference will be to use IPv6 and terminate the IPv4 connection. If you aren't using Chrome then you should be aware of how IPv6 may or may not be enabled in your web browser.
Cisco has a page on their Cisco Support Community site dedicated to World IPv6 Day. You can check in here during the day on activities and notes from others. Another way to keep informed on IPv6 events is to check in on NetworkWorld's IPv6 Page.
Whatever happens on World IPv6 Day, we are sure to learn more about the Internet and the future of the transition to IPv6. It is going to be a bit like Groundhog day. If Punxsutawney Phil sees his shadow then the groundhog will return to the burrow for the rest of the longer winter. If the groundhog emerges from his burrow and does not see his shadow then the winter will be shorter. If World IPv6 Day convinces the Internet community that it is safe to come out of their burrows then we may see an end to the hesitance to deploy IPv6. I am hoping that the Internet content providers don't see their own shadow and we will see an accelerated push for IPv6 in the coming years.