benjojo blog

How far can you go with IX Route Servers only?

Some interesting stuff I found on IX LANs These days the internet as a whole is mostly constructed out of point to point ethernet circuits, meaning an ethernet interface (mostly optical) attached

Picking uncontested private IP subnets with usage data If the device you are reading this on has an IPv4 address, it is very likely not a publicly routeable one.

BGP handling bug causes widespread internet routing instability At 7AM (UTC) on Tuesday May 20th 2025 a BGP message was propagated that triggered surprising (to many) behaviours with two major BGP

Building Ultra Long Range TOSLINK This post is a textual version of a talk I gave at The 38th Chaos Computer Congress at the end of 2024

The “simple” 38 step journey to getting an RFC The Internet is built on the mutual understanding of network protocols and practices, and most of those protocols are defined using Request For Comments (RFC) or Best Common Practices (BCP) documents.

Flexing the Windows RRAS BGP implementation At this point I am a bit of a BGP protocol implementation connoisseur thanks to

Better IX network quality monitoring This post is a textual version of a talk I gave at the first NetUK.

Reclaiming IPv4 Class E’s 240.0.0.0/4 A video recording of

Sysadmin friendly high speed ethernet switching I’ve been on the lookout for a ethernet switch that I don’t hate, the problem with a lot of higher

Signed but not secure At the start of the year a very interesting (and some would say inevitable) event happened involving internet routing security, the first case study of a large-scale victim o

Appreciation of automated IX Quarantine LAN testing Something that bgp.tools (my company) does a great deal is joining internet exchanges.

Where is all of the fediverse?

The browsers biggest TLS mistake Much like a previous talk of mine at Chaos Computer Congress this blog post is a direct write-up of a talk, if you prefer to consume this kind

Grave flaws in BGP Error handling Border Gateway Protocol is the de facto protocol that directs routing decisions between different ISP networks, and is generally known as the “glue”

Driver adventures for a 1999 webcam We generally know that when we buy a piece of technology that it will not last forever, connectors wear out and/or go out of fashion.

Going multipath without Multipath TCP Gigabit ethernet has been around for a long time, it’s so ubiquitous that there is a very strong chance that if you have a RJ-45 port on your compu

Who is squatting IPv4 addresses?

LTO Tape data storage for Linux nerds Tape storage is surprisingly not dead!

Ghost in the ethernet optic A few months ago I stumbled on a tweet pointing out a kind of [SFP optic](https://en.wikiped

One of these JPEGs is not like the other “JPEG” or the image encoding specification by the “Joint Photographic Experts Group” (JPEG) is a truly universal format at this stage.

Imaging mounted disk volumes under duress Backups are critical.

Hunting down the stuck BGP routes BGP is the glue between all of the thousands of border routers that make up the internet (you can find this post (battleships) and [this post (EvE)](https://blog.b

Splitting the ping Ping is one of the fundamental pillars of networking.

Hacking Ethernet out of Fibre Channel cards This story, like another in the past, started as an eBay purchase that I wo

Stressing the network when it’s already down [Impact by Eric Wienke, edits by Ben Cartwright-

How 1500 bytes became the MTU of the internet Translations

Writing userspace USB drivers for abandoned devices Transl

You cannot cURL under pressure cURL.

The year of RPKI on the control plane This post is a textual version of the talk I gave at NLNOG 2019, You can watch the recording of the talk on youtube below if that’s your preferred medium: <iframe width=“700” height=“328” src=“https://www.

Teaching a cheap ethernet switch new tricks Ethernet rules everything around us, a large proportion of our systems communicate to each other with ethernet somewhere in the line.

The speed of BGP network propagation

What would a EvE online Internet look like?

A dive into the world of MS-DOS viruses Translations are available in: <a hre

The state of RPKI: Q4 2018 In the fall I did a blog post and talk on RPKI about how the current methods of measuring RPKI deployment are broken because they do not take

From VNC to reverse shell Personal websites are weird.

Are BGPs security features working yet?

Building telemetry for tea aka Tealemetry As a British person, I admittedly conform to the stereotype of tea consumption, and giving I’ve been consuming tea for most of my life I have gained opinions on all kinds of tea based variables.

The death of a TLD Another one bites the dust.

Calling the world cup goals 5 seconds before they happen It’s that time again where once every 4 years people get very hyped over kicking a ball around a grass pitch, however this time my own country is actually doing pretty well!

The ISPs sharing your DNS query data DNS is fundamental to how the web works, and for most of the population it’s completely transparent.

x86 assembly doesn’t have to be scary (interactive) Assembly programming can be intimidating for people who have never looked into it any deeper than a glance, but giving that it underpins how the computers we use work it can be helpful having cont

Payments with less of the evil I hate card networks.

Playing battleships over BGP BGP is the glue of the internet.

Yubikey/Smartcard backed TLS servers It has become clear that storing secrets in computers is hard.

Making art with SSH key randomart SSH is everywhere in the development or operations world now.

Mapping the whole internet with Hilbert curves Translations are available in:

Encoding data in dubstep drops [Warning: Those who can’t stand EDM/dubstep, oh boy do I have bad news for you in regards to this blog post] Dubstep songs are often criticized as sounding extremely computer generated and often just too aggressi

Giving every Tor Hidden Service a IPv6 address Tor has a neat feature called Onion Services [(A)](https://web.archive.org/web/20180330000120/https://www.torproject.org/docs/onion-services.h

DNSFS.