Image couldn't load - you don't seem to have IPv6 connectivity

blog topics: BGP · IPv6 · more · my publications · my business: inet⁶ consult · contact: Twitter · LinkedIn · email · 🇺🇸 🇳🇱

This is the main page of the site. Archive for 2019.

A new beginning

It's time for something new: after three years as a network architect at Logius, I'm going back into business for myself.

I'm going to focus on providing advice about connectivity to the internet to organizations for which an internet connection is a critical asset.

Watch this space for more information!

Permalink - posted 2019-02-28

Een nieuw begin

Het is tijd voor een nieuwe uitdaging: na drie jaar als netwerkarchitect bij Logius begin ik vanaf 1 maart weer voor mezelf.

Hierbij richt ik me op het adviseren over connectiviteit naar het internet aan organisaties waarvoor een internetverbinding een kritisch bedrijfsmiddel is.

Hou deze plek in de gaten voor meer informatie!

Permalink - posted 2019-02-28

Dark mode!

Last year Apple introduced dark mode in MacOS. This is really nice at night because your eyeballs aren't blasted with tons of white backgrounds in pretty much all windows. Unfortunately, most web pages still use a white background. Obviously you can redesign your website to conform to dark mode, but this looks rather stark on computers in light mode.

The solution would be to have your website render dark on a system in dark mode and light on a system in light mode. As of the new version of Safari included in MacOS 10.14.4 Mojave that was released just now, you can actually do that, as you can see here. Just switch your system between light and dark mode and you'll see this webpage switch over accordingly.

I like to use this terminal command to switch between light and dark mode:

sleep 2; osascript -e 'tell application "System Events" to tell appearance preferences to set dark mode to not dark mode'

(Change the last "not dark mode" to "true" or "false" to enable or disable dark mode. The line above toggles back and forth.)

On your website you need to set up conditional CSS with media queries. This is what I use:

<style type="text/css" media="screen, print">
  body { background-color: #f0f0f0; }
  A { color: #c00000; text-decoration: underline; }
  A:visited { color: #700000; text-decoration: underline; }
  H1 { font-family: futura, arial, sans-serif; font-size: 14pt; }
<style type="text/css" media="screen and (prefers-color-scheme: dark)">
  body { background-color: #202020; color: #d0d0d0; }
  A { color: #ff6734; }
  A:visited { color: #d82000; }

The first part between sets everything up for light mode, with a very light gray background.

Then the second style section (in bold) with (prefers-color-scheme: dark) overrides those earlier color settings. Note that all the font settings from the first style section are inherited by the second style section; no need to restate all of those.

That's it! Pretty cool, right?

Update: have a look here for more information, including how to use dark mode with javascript.

Permalink - posted 2019-03-26

Dubbele regenboog!

Image link - posted 2019-04-25

→ 🇪🇺 Ja, er valt echt iets te kiezen bij de verkiezingen voor het Europees Parlement

Morgen zijn de verkiezingen voor de Nederlandse afgevaardigden naar het Europees Parlement. Ik had half-en-half het plan om hier een stukje te schrijven over wat nu de relatie is tussen de Nederlandse partijen en de Europese fracties waar zij deel van uitmaken. Maar: Stuk Rood Vlees heeft dit veel beter gedaan dan ik kon!

Absolute aanrader om deze blogpost te lezen.

De echte uitslagen komen pas zondagavond om 23 u nadat de stembussen de alle overige landen ook gesloten zijn, maar naar verwachting zal er donderdagavond wel een exitpoll zijn en wat uitslagen van individuele stembureaus.

Ik ben ook erg benieuwd naar de Britse uitslagen en de consequenties die met name de Tories hieraan zullen verbinden voor de brexit.

Read the article - posted 2019-05-22

112-storing: hoe voorkomen we zulke problemen op het internet?

Afgelopen maandagmiddag was er een grote storing in het telefonienetwerk van KPN, waarbij ondermeer het alarmnummer 112 zo'n drie uur niet bereikbaar was. Hoe kan het dat een telefoontje op een vaste lijn van KPN naar een meldkamer in de veiligheidsregio Groningen last heeft van dezelfde storing als een telefoontje van een Vodafone-gebruiker naar een meldkamer in de veiligheidsregio Limburg-Zuid? Dinsdag kwam het antwoord: een softwarefout. Het mocht niet baten dat het betreffende systeem viervoudig uitgevoerd was.

Intelligent network

In de telefonie is al vele jaren geleden het zogenaamde intelligent network ingevoerd. Voor die tijd waren vaste nummers gekoppeld aan wijkcentrales en mobiele nummers aan de mobiele operator. Als je dus van de ene kant van de stad naar de andere verhuisde, of van de ene mobiele operator naar de andere, dan kreeg je een nieuw nummer. Met IN was dat niet meer nodig: de telefooncentrale vraag aan een centrale database waar telefoontjes naartoe gerouteerd moeten worden. Probleem is wel dat het telefoonnetwerk nu afhankelijk is van een klein aantal centrale systemen. (En Voice over IP (VoIP) heeft dat versterkt.) Voorheen kon je nog binnen je eigen stadsdeel bellen zolang de wijkcentrale het deed, ook al lag de rest van het telefoonnetwerk plat.

Internetrouters worden afhankelijk van centrale systemen

We zien nu dezelfde ontwikkeling op ons af komen in de internetwereld. (...)

Read the article - posted 2019-06-25

Slides: Validating the BGP AS path with RPKI

Slides from my presentation about validating the BGP AS path with RPKI at the Euro-IX Route Server Workshop Amsterdam, 18 July 2019.

Permalink - posted 2019-07-18

4K TV part 1: what you need to know about the hardware

Although it says "4K TV", as far as I know, there's (virtually) no actual TV broadcast in 4K, so what I'm really talking about here is the state of home theater technology as of around 2018. This post is about the hardware and the formats. Part 2 will be about 4K content and whether the 4K thing is worth the money.

Read the article - posted 2019-08-22

4K TV part 2: 4K and Dolby Atmos content

So with all the technical details out of the way in part 1, let's have a look at where to get 4K content and whether it's worth the trouble and the expense. Where I've found 4K content...

Read the article - posted 2019-08-26

You can never have too many BGP books

Image link - posted 2019-09-09

Presentatie: BGP-beveiliging en route leaks

Mijn presentatie bij NiVo Network Architects over BGP-beveiliging en route leaks, 10 september 2019 in Weesp.

Permalink - posted 2019-09-10

Kilmaatmars Den Haag

Image link - posted 2019-09-30

Routing theory: are link state and distance vector the only games in town?

During his talk about 30 years of BGP, Geoff Huston said something along the lines of "someone should come up with another type of routing protocol besides distance vector and link state". That is of course too delicious a challenge to ignore...

Read the article - posted 2019-10-15

Storks on lampposts—our city birds here in The Hague

Image link - posted 2019-10-29

Airpods Pro

It's insane. I already spent nearly 800 euros on bluetooth headphones this year. And then Apple released the Airpods Pro, costing € 279 here in the Netherlands. And I couldn't help myself and bought a pair. So let's see how they compare...

Read the article - posted 2019-11-26

Weblog reorganized

I've reorganized my blog(s) and created subdomains under for different topics.

Read the article - posted 2019-11-26

Weblog gereorganiseerd

Ik heb mijn blog(s) gereorganiseerd, en onder subdomeinen aangemaakt voor verschillende onderwerpen.

Read the article - posted 2019-11-26

Europe runs out of IPv4 addresses even further, what now?

Less than three months ago I wrote about how the uptake of the remaining IPv4 addresses at RIPE was accelerating, with the RIPE NCC likely to run out of the addresses set aside in the "last /8" before the end of the year. And so they did, two days ago. So as of this week, it's no longer possible to request address space in the RIPE service region (Europe, former Soviet Union, Middle East) and get them within a somewhat predictable period...

Read the article - posted 2019-11-27

Slides: AS paths: long, longer, longest

Presentation slides from my lightning talk "AS paths: long, longer, longest" at the RIPE-79 meeting in Rotterdam, 18 October 2019.

Permalink - posted 2019-11-29

→ America is not the land of the free but one of monopolies so predatory they imperil the nation

Excellent piece by Observer/Guardian columnist Will Hutton based on the work of economist Thomas Philippon:

The news is that over the last 20 years per capita EU incomes have grown by 25% while the US’s have grown 21%


The US economy is becoming increasingly harmed by ever less competition, with fewer and fewer companies dominating sector after sector – from airlines to mobile phones.


But why has this happened now? Philippon has a deadly answer. A US political campaign costs 50 times more than one in Europe in terms of money spent for every vote cast. [...] Corporations want a return on their money, and the payback is protection from any kind of regulation, investigation or anti-monopoly policy that might strike at their ever-growing market power.

A real eye-opener.

Read the article - posted 2019-12-02

Time to turn off IPv4 (just a little)

Another month, and we'll be living in the 2020s. And yet, 70% of the internet is still IPv4-only. (I'll be writing a story looking back on IPv6 progress the past decade in January.) So I thought: maybe I should draw a line in the sand and turn off IPv4 for my website. But then how will those 70% find me, and all the links to older content will be dead to much of the internet. Click below to continue reading.

Note: this is an example of the warning image, your IPv6 connectivity may be fine!

Read the article - posted 2019-12-03

Tijd om IPv4 uit te zetten (een beetje)

Over een maand leven we in de jaren '20 van de 21e eeuw. En toch heeft 70% van het internet nog steeds alleen maar IPv4. (In januari schrijf ik een verhaal dat terugkijkt naar de voortgang van IPv6 in het afgelopen decennium.) Dus ik dacht: misschien moet ik een streep trekken en IPv4 uitschakelen voor mijn website. Maar dan kan 70% me niet meer vinden, en de links naar oudere artikelen zijn dan dood voor een groot deel van het internet. (Klik beneden om verder te lezen.)

Let op: dit is een voorbeeld van de waarschuwing, je IPv6-connectiviteit kan prima in orde zijn.

Read the article - posted 2019-12-03

After sunset

Image link - posted 2019-12-04

Fun with fonts!

After many years of using Century Gothic and its clone URW Gothic Book for my website, I felt it was time to reconsider that choice. So I went font hunting!

Over the course of my hunting expedition, found a nice new font, Muli, and I created a page that lets you compare different fonts and their weights interactively. Have a look.

Read the article - posted 2019-12-12

Bluesky: Twitter wants a federated Twitter

Twitter's Jack Dorsey, in (of course) a Twitter thread:

Twitter is funding a small independent team of up to five open source architects, engineers, and designers to develop an open and decentralized standard for social media. The goal is for Twitter to ultimately be a client of this standard.

This is interesting on several levels. I'll mostly talk about the protocol design part of this, but before I do that: when has a business that's pretty much in a monopolist position ever voluntarily given up that position? They must really be feeling the pushback against "content and conversation that sparks controversy and outrage", and see this as a way out.

Read the article - posted 2019-12-17


Image link - posted 2019-12-25

❝Beating BGP is harder than we thought❞

In a paper for the HotNets'19, seven researchers admit that "beating BGP is harder than we thought". (Discovered through Aaron '0x88cc' Glenn.) The researchers looked at techniques used by big content delivery networks, including Google, Microsoft and Facebook, to deliver content to users as quickly as possible. This varies from using DNS redirects to PoPs (points of presence) close to the user, using BGP anycast to route requests to a PoP closeby and keeping data within the CDN's network as long as possible ("late exit" or "colt potato" routing).

Turns out, all this extra effort only manages to beat BGP as deployed on the public internet a small fraction of the time.

Read the article - posted 2019-12-30

Search for:

Archives: 0