Starlink tells the world it has over 150 sextillion IPv6 addresses

But the data describing where they're used - which is help to fight crime - isn't very useful

Internetworking wonks have investigated Starlink’s use of IP addresses and found some interesting facts.

Internet infrastructure analyst Doug Madory on Wednesday used the Internet Society’s Pulse blog to share his analysis of the IP addresses Starlink lists in its IP geolocation file, the format network operators use to self-report where they use the IP addresses they hold.

Madory noted recent changes to Starlink’s file, which over the years has described an increasing quantity of IP address holdings.

According to his analysis, in April 2022 Starlink’s geolocation file mentioned 592 /24 IPv4 blocks – each of which covers 256 IP addresses. As of July, Elon Musk’s space ISP had 1,379 /24s, plus hundreds of smaller blocks, and therefore over 350,000 IPv4 addresses to play with.

Its IPv6 holdings are, as you would expect, vastly larger.

The entire IPv6 number space has 2¹²⁸ addresses – over 340 undecillion addresses.

According to Madory, in April 2022 Starlink’s file indicated it used 61 /36 blocks, each of which contains 2⁹² addresses – or about 4.95 sextillion addresses. As of July this year, Starlink’s geolocation file mentioned 383 /40 blocks (2⁸⁸ addresses, or around 390 quintillion apiece) plus 24 /41s (2⁸⁷ each or 154 quintillion) and 205 /42s (2⁸⁶ or 77 quintillion). In October, Madory spotted another 86 /40s in Starlink’s files.

The math is head-spinning, but we think Starlink’s geolocation data mentions over 150 sextillion IPv6 addresses - a smaller number than its files mentioned three years ago.

Whatever the true number, it's colossal. Starlink is almost certainly not using them all and probably won’t because the intricacies of internetworking mean it’s not practical to use all addresses.

Where in the world is Starlink?

Geoff Huston, chief scientist at the Asia Pacific Network Information Centre (APNIC) has also looked at Starlink’s IP geolocation data and found some oddities.

In a September post he pointed out that geolocating IP addresses matters because it has “obvious uses in the ongoing fight against various forms of cyberattacks, trying to de-anonymize the identity and location of the attacker.”

“This information is also used in attempting to enforce various intellectual property rights that are often assigned to rights holders on an economy-by-economy basis,” he wrote.

But Huston feels current measurement techniques for IP geolocation struggle to handle widespread satellite internet adoption – and cites results that suggest six million people in Yemen (which is home to 10 million netizens) use Starlink as an example. He thinks one possible explanation for that odd result is that ships at sea passing Yemen on their way to the Suez Canal use Starlink. But he also noted that as just 60 ships a day use the Canal, even all the vessels in transit can’t explain the amount of Starlink users.

His alternative theory is that Starlink uses Yemen as a base to distribute terminals to other countries.

“There have been persistent stories in several markets of Starlink resellers that set up a service in an economy that has the necessary national regulatory approvals to use Starlink, and then they ship the dish to a nearby location in a different economy,” Huston wrote. “It’s an open question as to the extent this is taking place, and if so, then it’s certainly plausible to guess that users in Saudi Arabia are using Starlink services that are registered in Yemen.”

Huston pointed to many other anomalies in Starlink geolocation data, such as the apparent 6,000-plus users on Saint Barthelmy, an overseas ‘collectivity’ of France with a population of 9,000 people.

“Its former status was a commune as part of Guadeloupe,” Huston wrote. “While the Starlink geolocation database distinguishes between Guadeloupe and Saint Barthelmy, it appears that other databases do not draw a distinction between the two, hence the very high proportion of placements in this economy.”

Due to the problems outlined above, and other issues elsewhere, Huston decided to override Starlink geolocation data in 20 economies listed in his post and instead assigned an ‘unclassified’ designation to part of the Starlink geolocation data.

“It’s not exactly a satisfying response to the problem, but it stops the distortion of the national measurements due to the increasing levels of usage of these satellite-based services for Internet access,” he wrote. ®