Category Archives for "Potaroo blog"

DNS Query Privacy

In this article we'll look at DNS Query Name Minimisation in some detail and present the results of our measurement of the current level of use of this resolver query technique in today's Internet.

TCP MSS Values

It may sound a little esoteric, but after a recently exposed Linux vulnerability the setting of the MSS value in a TCP handshake evidently matters. What values are used out there in the Internet today?

Not So Private Thoughts at IETF 105

At IETF 105, held in Montreal at the end of July, the Technical Plenary part of the meeting had two speakers on the topic of privacy in today's Internet, Associate Professor Arvind Narayanan of Princeton University and Professor Stephen Bellovin of Colombia University. They were both quite disturbing talks in their distinct ways, and I'd like to share my impressions of these two presentations and then consider what privacy means for me in today's Internet.

Looking for What’s Not There

DNSSEC is often viewed as a solution looking for a problem. It seems only logical that there is some intrinsic value in being able to explicitly verify the veracity and currency of responses received from DNS queries, yet fleshing this proposition out with practical examples has proved challenging. Where else might DNSSEC be useful?

Network Protocols and their Use

In June I participated in a workshop, organized by the Internet Architecture Board, on the topic of protocol design and effect, looking at the differences between initial design expectations and deployment realities. These are my impressions of the discussions that took place at this workshop.

Happy Birthday BGP

The first RFC describing BGP, RFC 1105, was published in June 1989, thirty years ago. That makes BGP a venerable protocol in the internet context and considering that it holds the Internet together it's still a central piece of the Internet's infrastructure. How has this critically important routing protocol fared over these thirty years and what are its future prospects? It BGP approaching its dotage or will it be a feature of the Internet for decades to come?

Expanding the DNS Root: Hyperlocal vs NSEC Caching

The root zone of the DNS has been the focal point of many DNS conversations for decades. One set of conversations, which is a major preoccupation of ICANN meetings, concerns what labels are contained in the root zone. A separate set of conversations concern how this root zone is served in the context of the DNS resolution protocol. In this article I'd like to look at the second topic, and, in particular, look at two proposals to augment the way the root zone is served to the DNS.

More DOH

DOH is not going away. It seems that the previous article on DOH has generated some reaction, and also there is some further development that should be reported, all of which I'll cover here.

DNS Privacy at IETF 104

From time to time the IETF seriously grapples with its role with respect to technology relating to users' privacy. Should the IETF publish standard specifications of technologies that facilitate third party eavesdropping on communications or should it refrain from working on such technologies? Should the IETF take further steps and publish standard specifications of technologies that directly impede various forms of third party eavesdropping on communications? Is a consistent position from the IETF on personal privacy preferred? Or should the IETF be as agnostic as possible and publish protocol specifications based solely on technical coherency and interoperability without particular regard to issues of personal privacy? This issue surfaced at IETF 104 in the context of discussions of DNS over HTTPS, or DOH.

The State of DNSSEC Validation

Many aspects of technology adoption in the Internet over time show simple "up and to the right" curves. What lies behind these curves is the assumption that once a decision is made to deploy a technology the decision is not subsequently "unmade." When we observe an adoption curve fall rather than rise, then it’s reasonable to ask what is going on.

A quick look at QUIC

Quick UDP Internet Connection (QUIC) is a network protocol initially developed and deployed by Google, and now being standardized in the Internet Engineering Task Force. In this article we’ll take a quick tour of QUIC, looking at what goals influenced its design, and what implications QUIC might have on the overall architecture of the Internet Protocol.


What part of "no" doesn't the DNS understand? We look at over-query rates in the DNS when we try to resolve a non-existent name.

Addressing 2018

Time for another annual roundup from the world of IP addresses. Let's see what has changed in the past 12 months in addressing the Internet and look at how IP address allocation information can inform us of the changing nature of the network itself.

BGP in 2018 – Part2: BGP Churn

The scalability of BGP as the Internet’s routing protocol is not just dependant on the number of prefixes carried in the routing table. Dynamic routing updates are also part of this story. If the update rate of BGP is growing faster than we can deploy processing capability to match then the routing system will lose data, and at that point the routing system will head into turgid instability. This second part of the report of BGP across 2018 will look at the profile of BGP updates across 2018 to assess whether the stability of the routing system, as measured by the level of BGP update activity, is changing.

BGP in 2018 – Part1: The BGP Table

It has become either a tradition, or a habit, each January for me to report on the experience with the inter-domain routing system over the past year, looking in some detail at some metrics from the routing system that can show the essential shape and behaviour of the underlying interconnection fabric of the Internet.

IPv6 in China

China has an estimated Internet user population of 741 million, out of a total population of 1.4 billion people. If there was extensive deployment of IPv6 services in China, then the case that IPv6 has already achieved critical mass of deployment would be easy to make. On the other hand, if such a significant user population had no IPv6 service and no visible plans for IPv6 services, then the entire conversation about the times and certainties about the future of IPv6 takes on a different direction. Which means that China matters in the world of IPv6. It matters a lot.

Internet Economics

The way in which we communicate, and the manner, richness and reach of our communications has a profound impact on the shape and function of our economy and our society, so its perhaps entirely proper that considerations of the manner in which we develop and tune public policies in this industry take place in open forums. One way is to bring together the various facets of how we build, operate and use the Internet and look at these activities from a perspective of economics and public policy.

What’s the Time?

Computers have always had clocks. Knowing the time is important to many computer functions. In a networked world its not only important to know the time, but its equally important to know the right time. But how accurate are all these computer clocks? Lets find out.
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