Category Archives for "Potaroo blog"


The world of cryptographic algorithms is one that constantly evolves and increasing key sizes in the venerable RSA crypto algorithm is a source of concern for DNSSEC. The response to this escalation in key sizes is to look at alternative forms of public-key algorithms which have a higher cryptographic “density”, using elliptic curve cryptography. Here we will look at the level of Internet support provided for a recent crypto offering, the Edwards curve algorithm Ed25519.

DNS Centrality

How did we get to here? How did a network technology such as the Internet, which was designed to pass control away from the central network to the connected devices succumb to unprecedented levels of centrality?

Transport vs Network

According to the OSI Reference Model for network protocols it should not matter in the slightest what value you put in the IP protocol field in IP packet headers. It’s really none of the network's business! but in today’s public Internet it appears to matter a lot that the transport protocol header is visible to the network. Why?

IPv4 in the Headlines

The world of IPv4 addresses is a relatively obscure backwater of the Internet. All that drama of IPv4 address exhaustion happened with little in the way of mainstream media attention. So it came as a bit of a surprise to see a recent headline in the Washington Post about IPv4 addresses.

IPv6 Fragmentation Loss

In this report I would like to revisit this measurement of packet drop for IPv6 Fragmented packets and see if the picture has changed over the intervening four years since we last measured this behaviour.

DNS at IETF 110

The amount of activity in the DNS in the IETF seems to be growing every meeting. I thought that the best way to illustrate to considerably body of DNS working being undertaken at the IETF these days would be to take a snapshot of DNS activity that was reported to the DNS-related Working Group meetings at IETF 110.

TCP Congestion Control at IETF 110

IETF 110 was held virtually in March 2020. These are some notes I took on the topic of current research activities in the area of transport protocol flow control at the meeting of the Internet Congestion Control Research Group at that meeting.

Measuring ROAs and ROV

In 2020 APNIC Labs set up a measurement system for the validators. What we were trying to provide was a detailed view of where invalid routes were being propagated, and also take a longitudinal view of how things are changing over time. The report is at and the description of the measurement is at I'd like to update this description with some work we’ve done on this measurement platform in recent months.

Notes from NANOG 81

As the pandemic continues, the network operational community continues to meet online. NANOG held its 81st meeting on February 8 and 9, and these are my notes from some of the presentations at that meeting.

An IPv6 Update for 2020

The common theme of many of reviews of the Internet in 2020 has been that the Internet has been used to plug the gap caused by shutting down many of our physical venues where we previously worked and played. No matter what aspect of the Internet you look at, its clear that we all made much more use of the Internet this year. Here I would like to ask the inevitable IPv6 question: What role did IPv6 play in 2020?

The Internet of Trash

It's often a clear signal that we’re in in deep trouble when politicians believe that they need to lend a hand and help out with regulations. Either the actions of the market have failed consumers and some form of public action is necessary to address aspects of this failure, or the situation is so desperately broken and beyond help that the legislature is performing a largely ineffectual action that serves more to disclaim any residual responsibility on the part of the public sector for the mess that we’ve created.

Addressing 2020

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 2020 – BGP Update Churn

The first part of this report looked at the size of the routing table and looked at some projections of its growth for both IPv4 and IPv6. However, the scalability of BGP as the Internet’s routing protocol also is related to the rate of dynamic routing updates. If the update rate of BGP is growing faster than we can deploy processing capability to match, then the routing system will lose coherence, and at that point the network will head into periods of instability. This second part of the BGP report looks at the profile of BGP updates across 2020

BGP in 2020 – The BGP Table

At the start of each year I have been reporting on the behaviour of the inter-domain routing system over the past 12 months, 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.

DNS Oblivion

The problem with both DoH and DoT is that neither is all that satisfactory from a privacy standpoint. It is more of a compromise approach that poses a difficult question to me, as the end user. If I have to compromise my privacy to a third party and expose the combination of my identity and the DNS queries I make, then who should be privy to this information? Which third party DNS provider represents the least risk to me now and in the future? It's a tough question, and the best answer not having to compromise my privacy at all.

DNS Flag Day 2020

One of the outcomes of the 'stacked' architecture of network protocol design is that upper level protocols should not try to do the job of the lower layers. Packet adaptation through fragmentation is a IP layer 'problem' and applications do not have to concern themselves with this. We've come some distance from this position and these days many applications need to be highly aware of transport layer and IP layer properties, and the DNS is no exception. There have been some recent steps in the DNS with the DNS Flag Day 2020 to try and tune the DNS to avoid packet fragmentation. How bad is the problem with packet fragmentation and do the DNS Flag Day measures address the issue?


This is the second part of a technical report on a detailed exploration of the way the Internet’s Domain Name System (DNS) interacts with the network when the size of the application transactions exceeds the underlying packet size limitations of hosts and networks. In this part we explore UDP-only and TCP-only behavious and also look at how to maximise the resilience of the DNS when handling larger responses.
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