Lightning Talk: Signaling End-User Prefix Sizes Using Prefixlen Files @TeamNANOG

Uploaded June 2026 | Updated September 2026, 1 week ago

presented by Oliver Gasser
IP addresses or prefixes are often times used as a proxy to identify users. When multiple users are sharing a prefix or even an IP address in the case of Carrier Grade NAT, this can have negative consequences for other users, such as being detected as a bot, needing to solve CAPTCHAs, or their access simply being blocked. In this lightning talk I'll present prefixlen files as a way to solve this. Prefixlen files have been recently (last week) standardized by the IETF as RFC 9977. The talk's goal is to make network operators as well as service providers aware of prefixlen files.

nanog.org/events/nanog-97/content/5800

Lightning Talk: Signaling End-User Prefix Sizes Using Prefixlen Files

$Towards a Non-Binary View of IPv6 Adoption Abstract Twelve years have passed since World IPv6 Launch Day, but what is the current state of IPv6 deployment? Prior work has examined IPv6 status as a binary: can a user do any IPv6? As deployment increases, we must consider a more nuanced, non-binary perspective on IPv6: How much, and how often, can a user or a service use IPv6? We consider this question as a client, server, and cloud provider. Considering the clients perspective, we observe user traffic. We see that the fraction of IPv6 traffic a user sends varies greatly, both across users and day-by-day, with a standard deviation of over 15%. We show this variation occurs for two main reasons. First, IPv6 traffic is primarily human-generated, thus showing diurnal patterns. Second, some services lead with full IPv6 adoption, while others lag with partial or no support, so as users do different things their fraction of IPv6 varies. We look at server-side IPv6 adoption in two ways. First, we expand analysis of web services to examine how many are only partially IPv6 enabled due to their reliance on IPv4-only resources. Our findings reveal that only 12.6% of top 100k websites qualify as fully IPv6-ready. Finally, we examine cloud support for IPv6. Although all clouds and CDNs support IPv6, we find that tenant deployment rates vary significantly across providers. We find that ease of enabling IPv6 in the cloud is correlated with tenant IPv6 adoption rates, and recommend best practices for cloud providers to improve IPv6 adoption. Our results suggest IPv6 deployment is growing, but many services lag, presenting a potential for improvement. Sulyab Thottungal Valapu: Sulyab Thottungal Valapu is a Ph.D. candidate at the University of Southern California, advised by John Heidemann. His research uses Internet measurement to understand the real-world effects of the Internets evolution, with a focus on the operational, security, and privacy implications of changes in Internet protocols and naming systems. Before his Ph.D., Sulyab worked as a software engineer at Arista Networks. https://nanog.org/events/nanog-97/content/5748/$

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