The original internet architecture, built atop Internet Protocol Version 4 (IPv4), allocated less than 4.3 billion addresses. Every internet connected device needs an IP address, but in the early days of the internet there were no tablets or smartphones and computers were luxuries, not commodities.
Today, there are almost as many smartphones as there are IPv4 addresses (~3.5 billion smartphones at the time of writing in 2020). Numerous measures have been put in place to ration IPv4 addresses, including sharing of addresses across multiple devices within a local network. Since the late 1990’s, IPv6 has made great strides at becoming a long-term replacement for IPv4, offering nearly 3.4×10³⁸ addresses.
IPv6 deployment is steadily underway across many parts of the world, with many telecom companies in emerging markets leading the way. Reliance Jio in India, for example, is well ahead of many American companies at 90% IPv6 deployment. This should not come as a surprise given that India has the second largest total population at more than 1.35 billion. IPv4 simply cannot scale to support nations of that size.
IPv6 and Podcasting
Podcasts are essentially RSS feeds and audio files distributed via podcast hosts on servers around the world. There are two components that need to support IPv6: the client operating system and the podcast host server. Most client operating systems, including Apple iOS and Google Android 5.0+, support IPv6 (although Android still has IPv6-related limitations in 2020).
It is not enough for client operating systems to support IPv6; podcast hosts must also provide support. At minimum, this includes three key components.
- AAAA DNS records
- IPv6-compliant web server
- IPv6 DNS server
IPv6 support usually coexists with IPv4 support in what is called dual-stack delivery, so it is not a situation of IPv6 or IPv4 bur rather IPv6 and IPv4. Developers do not have to choose between the two. For cloud-native hosts, IPv6 support is often as simple as checking a box, and usually comes at no additional cost.
For podcasters, every redirect also needs to support IPv6. That means tracking and measurement services like Podtrac and Chartable need to support IPv6, in addition to the podcast host. Otherwise IPv6-only clients will still fail to resolve a DNS entry and ultimately be unable to listen.
Who supports IPv6?
Few podcast hosts provide public documentation regarding their support, or lack thereof, of IPv6 support. Doing some basic testing on a limited example set, these were my results among popular hosts:
No IPv6 Support: Libsyn, SoundCloud, Anchor.fm, Podomatic, BlogTalk, Spreaker, Simplecast, Ivoox, Megaphone, Art19, Feedpress, Blubrry, Podtrac, and Chartable
These results may not be fully conclusive, as it is possible for sites to partially support IPv6 only on specific subdomains or within specific paths. However, it seems systematic that many podcast hosts simply do not offer support for distributing content over IPv6.
Some of the largest podcast hosts still do not support IPv6 in 2020, which means many of the most popular podcasts from around the world are only accessible to listeners connecting via IPv4.
Why not support IPv6 support?
The only common case we heard about [for disabling IPv6 support] was internal IP address processing. — AWS FAQs
While the IAB Measurement Guidelines require IP addresses be used as part of a solution to identify unique listens, for reasons of data privacy and security, it is better for businesses to convert IPv4 or IPv6 into one-way hashes, both to anonymize user data and also standardize formatting. i.e. IPv4 and IPv6 addresses are formatted differently, but a hashing function like MD5 processes variable-length inputs into fixed-length outputs.
One notable example of IP address processing is GeoIP look-ups that map IP addresses to approximate physical locations. This is how localized podcasts like NPR’s ‘Consider This’ are able to adapt programming by geography. IP Geolocation is still possible on IPv6, but it is a bit more complicated. Supporting IPv6 would require hosts and analytics services make code modifications to handle GeoIP look-ups for both IPv4 and IPv6 addresses.
Potential Benefits of IPv6
IAB Measurement Guidelines note that there are potential issues with, “shared locations such as corporate offices, dorms etc., that have a large number of people sharing the external IP Address.” With IPv6, every device can have its own, unique IP address. That means IPv6 can improve analytics accuracy by reducing or eliminating the use of shared IP addresses, as well as improve performance and security for listeners.
In IPv6, addresses could be static since there are many more IPv6 addresses than connecting devices globally. This would mean an IPv6 address is basically a UUID. Due to the security and privacy concerns this raises, IP addresses rotate on a regular basis on most residential and cellular networks. This in turn creates a challenge for accurate analytics. In many settings, session cookies or similar tracking technologies can be used to overcome some of these challenges.
Podcasting has largely been focused on developed markets like the US and EU, where IPv6 support now lags behind much of the developing world. Without business incentive, there is no compelling case for podcast hosts to offer IPv6 support. Worse, since IPv6-only users fail to establish a connection to an IPv4-only host, podcast hosts and podcasters have no visibility into how many listeners they may be missing out on.
Some podcasters may not see this as a problem, but OEMs and telecom companies like Reliance Jio often make IPv6-only the default configuration for devices like the JioPhone. In a 2019 presentation, Leveraging IPv6 for Explosive Growth, Ramesh Chandra of Reliance Jio writes:
- 93.7% requests served are on IPv6
- Jio’s exponential growth enabler is IPv6 (soon to be IPv6-only)
- Jio no longer encouraging IPv4 addresses
By not supporting IPv6, you are unnecessarily disregarding access to some of the largest and fastest-growing Anglophone markets like India.
As the developer of PodLP, listeners from around the world have reported issues accessing their favorite content on KaiOS mobile devices due to network connectivity issues related to a lack of IPv6 support. For podcasters and podcast hosts, the bottom line is this: if you do not support IPv6, you are losing listeners, especially in emerging markets.
IPv6 deployment is inevitable, and with it come gains in efficiency and security beyond the scope of in this article. There are entire podcasts like IPv6 Buzz dedicated to IPv6 networking concerns. Given it a listen, and consider how IPv6 could benefit you and your listeners.