benjojo blog

How far can you go with IX Route Servers only?

ben@benjojo.co.uk — Thu, 12 Mar 2026 11:32:39 +0000

How far can you go with IX Route Servers only?

On paper internet exchanges (IX) are very simple in their implementation, simply put together a bunch of routers on a shared layer 2 ethernet switch

Some interesting stuff I found on IX LANs

ben@benjojo.co.uk — Thu, 25 Sep 2025 09:12:44 +0000

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

ben@benjojo.co.uk — Thu, 05 Jun 2025 10:32:11 +0000

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. This is because the wide scale dep

BGP handling bug causes widespread internet routing instability

ben@benjojo.co.uk — Tue, 27 May 2025 10:45:56 +0000

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

ben@benjojo.co.uk — Tue, 07 Jan 2025 12:24:27 +0000

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

ben@benjojo.co.uk — Thu, 05 Dec 2024 10:43:41 +0000

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

ben@benjojo.co.uk — Thu, 26 Sep 2024 10:01:55 +0000

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

ben@benjojo.co.uk — Thu, 22 Aug 2024 10:47:42 +0000

Better IX network quality monitoring

This post is a textual version of a talk I gave at the first NetUK. You can watch the talk on YouTube that was recorded by the wonderful AV team below if that’s your preferred medium:

Reclaiming IPv4 Class E's 240.0.0.0/4

ben@benjojo.co.uk — Mon, 27 May 2024 13:42:52 +0000

Reclaiming IPv4 Class E’s 240.0.0.0/4

A video recording of

Sysadmin friendly high speed ethernet switching

ben@benjojo.co.uk — Thu, 18 Apr 2024 10:05:46 +0000

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

ben@benjojo.co.uk — Thu, 21 Mar 2024 16:31:30 +0000

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

ben@benjojo.co.uk — Thu, 01 Feb 2024 11:27:29 +0000

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?

ben@benjojo.co.uk — Fri, 12 Jan 2024 12:34:50 +0000

Where is all of the fediverse?

Spurred on by the problems at Twitter, a lot of my social media timeline has “moved out” of Twitter/“X” on to what people mostly describe as mastodon or

The browsers biggest TLS mistake

ben@benjojo.co.uk — Sun, 07 Jan 2024 15:13:50 +0000

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

ben@benjojo.co.uk — Tue, 29 Aug 2023 10:45:00 +0000

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

ben@benjojo.co.uk — Fri, 28 Apr 2023 10:18:30 +0000

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. But I think the most frust

Going multipath without Multipath TCP

ben@benjojo.co.uk — Thu, 24 Feb 2022 11:40:05 +0000

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?

ben@benjojo.co.uk — Thu, 17 Feb 2022 11:30:04 +0000

Who is squatting IPv4 addresses?

It’s an established fact on the internet that we have ran out of IP(v4) addresses, and we are st

LTO Tape data storage for Linux nerds

ben@benjojo.co.uk — Thu, 27 Jan 2022 11:23:54 +0000

LTO Tape data storage for Linux nerds

Tape storage is surprisingly not dead! If you are here then you may be considering using LTO tape as part of your backup or your long t

Ghost in the ethernet optic

ben@benjojo.co.uk — Thu, 13 Jan 2022 11:43:54 +0000

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

ben@benjojo.co.uk — Fri, 19 Nov 2021 10:47:26 +0000

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. You really cannot go very far on the internet without seeing a JPEG file

Imaging mounted disk volumes under duress

ben@benjojo.co.uk — Mon, 20 Sep 2021 11:25:28 +0000

Imaging mounted disk volumes under duress

Backups are critical. If you are lucky and organised you have a set of useful backup primitives, such as Point in Time snapshots on your Infra

Hunting down the stuck BGP routes

ben@benjojo.co.uk — Wed, 21 Apr 2021 10:12:35 +0000

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

ben@benjojo.co.uk — Mon, 01 Mar 2021 11:57:53 +0000

Splitting the ping

Ping is one of the fundamental pillars of networking. It’s simple, universally supported, and is normally one of the f

Hacking Ethernet out of Fibre Channel cards

ben@benjojo.co.uk — Wed, 09 Sep 2020 10:32:42 +0000

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

ben@benjojo.co.uk — Thu, 30 Apr 2020 10:08:38 +0000

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

ben@benjojo.co.uk — Wed, 19 Feb 2020 11:48:55 +0000

How 1500 bytes became the MTU of the internet

Translations

Writing userspace USB drivers for abandoned devices

ben@benjojo.co.uk — Sun, 17 Nov 2019 12:39:16 +0000

Writing userspace USB drivers for abandoned devices

Transl

You cannot cURL under pressure

ben@benjojo.co.uk — Sat, 12 Oct 2019 11:54:07 +0000

You cannot cURL under pressure

cURL. The wonderful HTTP plumbing tool that powers both a lot of command line debugging and bash scripts, but also exists as a strong foundation in our applications in the form of libcurl.

The year of RPKI on the control plane

ben@benjojo.co.uk — Mon, 09 Sep 2019 12:38:20 +0000

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:

Teaching a cheap ethernet switch new tricks

ben@benjojo.co.uk — Thu, 13 Jun 2019 11:01:50 +0000

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. And the fast pac

The speed of BGP network propagation

ben@benjojo.co.uk — Sat, 04 May 2019 12:28:41 +0000

The speed of BGP network propagation

If you ever had to deal with bots while running a site you will have at least at some point looked into robots.txt, a system that isn’t rea

Propagation slow? Sound the alarms!

ben@benjojo.co.uk — Fri, 03 Jul 2015 14:39:24 +0000

Propagation slow? Sound the alarms!

This is a blog post that I had written for my employer CloudFlare You can find the full link here

CloudFlare operates a

Auditing GitHub users' SSH key quality

ben@benjojo.co.uk — Tue, 02 Jun 2015 13:22:03 +0000

Auditing GitHub users’ SSH key quality

Translations are available in: <a href

YAMware Old Malware can still be fun!

ben@benjojo.co.uk — Sun, 17 May 2015 16:54:53 +0000

YAMware Old Malware can still be fun!

(Side note, this blog post was written and then forgotten about quite a while ago, So I’ve finished it off, it was halfway done.)

While on holiday in the evenings with downtime to spare, I had realised that

Detecting anycast addresses and more

ben@benjojo.co.uk — Thu, 23 Apr 2015 20:20:18 +0000

Detecting anycast addresses and more

Anycast networks are a pretty interesting way to fix quite a few issues with networked services that involve needing global spread. One of the interesting things is that a computer cannot really tell (unless it

A peek into the USM format

ben@benjojo.co.uk — Sat, 21 Mar 2015 23:41:20 +0000

A peek into the USM format

A game that I really liked the visuals off, Crysis 3 uses a video file format called USM, This is a rather odd to me, since when I am used to pulling games apart for their assets, I am used to BINK video being used for th

Reverse Proxy + Cache for Minecraft

ben@benjojo.co.uk — Sun, 08 Feb 2015 21:49:37 +0000

Reverse Proxy + Cache for Minecraft

One of the things that I like to play from time to time is Minecraft, however one of things ( at least with me this is ) is that Minecraft is best played with other people, This however means you have to go throu

MITM'ing TLS/SSL for debugging purposes

ben@benjojo.co.uk — Thu, 05 Feb 2015 17:56:51 +0000

MITM’ing TLS/SSL for debugging purposes

From time to time you may want to debug TLS, Now this is not as easy as you might think, Because of the nature of TLS, you don’t really want to have anyone (even if they technically may have the key on the se

Thoughts on GitHub streaking

ben@benjojo.co.uk — Sun, 31 Aug 2014 18:21:56 +0000

Thoughts on GitHub streaking

Thought it might be a good idea to brain dump on my thoughts of “Write Code Everyday” and more to the point the [github challenge](http://ryanseys.com/blog/177-days-of-gith

Mumble: A referral was returned from the server.

ben@benjojo.co.uk — Sat, 31 May 2014 19:05:22 +0000

Mumble: A referral was returned from the server.

You may get A referral was returned from the server. when launching Digitally signed applications like Mumble on windows.

This is normally caused by the Digital Signature expiring. You can check

Lessons from APL, a "lost" language

ben@benjojo.co.uk — Mon, 26 May 2014 19:03:53 +0000

Lessons from APL, a “lost” language

A few weeks back the forum that I go on often held a obfuscation challenge, and people joked around about submitting a entry that was coded in APL.

APL (A Programming Language) is a programming language that w

NPM build error

ben@benjojo.co.uk — Sat, 19 Apr 2014 19:03:08 +0000

NPM build error

NPM has a bunch of useful stuff on it, however you could in life while using NPM get this:

stack Error: "pre" versions of node cannot be installed, use the --node dir flag instead

This error basically says “Give me the node

Dealing with MySQL resource shortage

ben@benjojo.co.uk — Thu, 17 Apr 2014 19:02:11 +0000

Dealing with MySQL resource shortage

You may in life while working with mysql get the following errors:

ERROR 1016 (HY000) at line 1: Can't open file: './blah/table.frm' (errno: 24)

``` SQL Error (23): Out of resources when o

Super Easy Twitter Bots

ben@benjojo.co.uk — Sun, 19 Jan 2014 19:00:11 +0000

Super Easy Twitter Bots

I often get really quite mad ideas on writing twitter bots, But I often get pretty bored of doing all of the boiler plate that is required when wanting to achieve these things.

The typical process to making a twitter bot

Running around HTTP firewalls

ben@benjojo.co.uk — Wed, 01 Jan 2014 20:58:36 +0000

Running around HTTP firewalls

When I was in 6th form and I wanted to get SSH access to my own systems I had quite a few issues doing so, Since port 22 was blocked and just about every other port was, For the first year that was fine however since