Security in DNS, TLSA records now available in our control panel to support DANE

February 11th, 2020 by

The Internet is better when it’s secure. Finally, thanks to Let’s Encrypt it’s possible to automatically get SSL certificates free of charge and as a result the Internet is dramatically more secure than it used to be. If you’ve used our DNS API you may have discovered that you can verify Let’s Encrypt SSL certificate requests using DNS records, including issuing wildcard certificates.

We support secure DNS (DNSSEC) which prevents DNS records from being forged, making the process of authenticating your SSL certificate through DNS records far more secure than the email-based authentication that was typically used for certificates issued by commercial certificate authorities. We have implemented support for CAA records which uses DNS to restrict the certificate authorities that can issue your certificates. This is most useful if the DNS is trustworthy which, again, requires DNSSEC.

However, there seems to be an opportunity here to improve things further. Rather than relying on a 3rd party certificate authority to confirm that you have control of your own DNS, why can’t you just publish your certificate in DNS directly? If you can trust DNS this would seem to be an obvious improvement, and with DNSSEC, DNS becomes trustworthy. We’ve now added support for the additional record type TLSA which allows exactly that, as part of DNS-Based Authentication of Named Entities (DANE).

Adding a TLSA record through our control panel.

DANE is a flexible mechanism that can be used to add an additional layer of security to certificates issued by a 3rd party authority, or to enable the use of self-signed certificates.

Unfortunately at the moment few clients support TLSA so for the majority of interactions you’re still going to rely on the certificate authority to verify the certificate. But implementations exist for both Exim and Postfix. Step by step, email is becoming more secure.

IPv6 updates

December 16th, 2019 by

Last Thursday we went to the IPv6 Council to speak about IPv6-only hosting and to exchange information with other networks about the state of IPv6 in the UK.

IPv4 address exhaustion is becoming ever more real: the USA and Europe have now run out, and Asia, Africa and Latin America all have less than a year of highly-restricted supply left.

Perhaps unsurprisingly, we’re now seeing real progress in deploying IPv6 across the board.

The major connectivity providers gave an update on their progress. Sky already have an effectively complete deployment across their UK network, so instead they told us about the Sky Italia build-out that launches early next year. It will initially be 100% dual stack but they’re planning to migrate to single stack IPv6 with IPv4 access provided by MAP-T as soon as possible. BT/EE have IPv6 virtually everywhere and take-up is rising as HomeHubs are retired and replaced with SmartHubs. Three are actively enabling IPv6 over their network, as we noticed last month:

Smaller providers are also making progress; Hyperoptic and Community Fibre have both essentially completed their dual stack rollout this year, with both organisations having to consider Network Address Translation due to lack of IPv4 addresses.

We’ve been working hard for many years to make IPv6-only hosting a practical option for our customers, allowing us to considerably expand the lifespan of our IPv4 allocation (which, thanks to a few acquisitions and being a relatively old company, is a reasonable size).

We heard from Ungliech, who started more recently and don’t have a large historical allocation of IPv4 addresses. They gave an interesting talk about their IPv6-only hosting and how it’s an urgent requirement for a new entrant because a RIPE final allocation of 1024 addresses isn’t enough to start a traditional hosting company. Thanks to RIPE running out last month, any new competitor has it four times harder with only 256 addresses to get them started.

We also had interesting updates from Microsoft about their continuing journey to IPv6-only internally in their corporate network, and the pain of continuing to support IPv4 private addressing. When they acquire a company they already have overlapping internal networks, and making internal services available to the wider organisation is an ongoing difficult challenge.

There was also a fascinating talk from SITA about providing network and infrastructure to aviation. There is a huge amount of networking involved and the RFC1918 private IPv4 address space is no longer large enough to enable a large airport. They have a very strong push to use IPv6 even on networks not connected to the public internet.

Updates to sympl to continue to support Let’s Encrypt

October 25th, 2019 by

Before you 3D print the keys from the photo, you should know they are no longer in use.

We’ve now updated Sympl to support the new ACME v2 protocol for long term Let’s Encrypt support.

Let’s Encrypt is changing the protocol for obtaining and renewing certificates from ACME v1, to ACME v2 and the version 1 protocol is now end-of-life. In the next few days (1st November) this means that new accounts will no longer be able to be registered which will prevent new sites obtaining SSL certificates. Final end of life occurs in 2021 when certificate renewals will start to generate errors and then fail entirely.

Symbiosis is now end of life, as Sympl is an actively developed fork we’d recommend any Symbiosis users migrate to Sympl. We’d also recommend our managed hosting as a good place to run your Sympl server.

Multiple Mythic Beasts staff members contributed to this update.

Let’s Encrypt support for older Debian

October 9th, 2019 by
seure cat

This cat is secure, but not dehydrated. (Credit Lizzie Charlton, @LizzieCharlton

Debian Jessie and Debian Stretch include dehydrated, a useful command line tool for managing Let’s Encrypt certificates. We use it fairly extensively for managing certificates throughout our servers and with our managed customers. Unfortunately due to a change in capitalisation at Let’s Encrypt, the standard copy of dehydrated shipped with Debian Jessie and Debian Stretch is no longer compatible. As there’s no package in backports, we’ve spun our own packages of a newer version of dehydrated which is available on our mirror server.

If you use the older version you’ll see an error like

"type": "urn:acme:error:badNonce",
"detail": "JWS has no anti-replay nonce",
"status": 400


“type”: “urn:ietf:params:acme:error:malformed”,
“detail”: “Malformed account ID in KeyID header URL: “””,
“status”: 400

The fix is very simple, you just need to install our dehydrated packages. This is very easy to do.

First add our signing keys

wget -O - -q | apt-key add -

Then the correct repository based on your version of Debian

echo deb jessie main >/etc/apt/sources.list.d/


echo deb stretch main >/etc/apt/sources.list.d/


apt-get update
apt-get install --only-upgrade dehydrated
dehydrated -c

and your copy of dehydrated will be updated to 0.6 and your certificates can be created as normal.

VMHaus services now available in Amsterdam

July 3rd, 2019 by

Integration can be hard work

Last year we had a busy time acquiring Retrosnub, BHost and VMHaus. We’ve been steadily making progress in the background integrating the services the companies provide to reduce costs and complexity of management. We can now also announce our first significant feature upgrade for VMHaus. We’ve deployed a new virtual server cluster to our Amsterdam location and VMHaus services are now available in Amsterdam. VMHaus is using Mythic Beasts for colocation and network and in Amsterdam they will gain access to our extensive set of peers at AMSIX, LINX and LoNAP. Per hour billed virtual servers are available from VMHaus with payment through Paypal.

As you’d expect, every VM comes with a /64 of IPv6 space.

In the background we’ve also been migrating former-BHost KVM-based services to Mythic Beasts VM services in Amsterdam. Shortly we’ll be starting to migrate former-BHost and VMHaus KVM-based services in London to new VM clusters in the Meridian Gate data centre.

Raspberry Pi on Raspberry Pi

June 22nd, 2019 by

Question: Is the Raspberry Pi 4 any good?
Answer: It’s good enough to run its own launch website with tens of millions of visitors.

Raspberry Pi 4 with PoE mounting points already attached.

The Raspberry Pi 4 is out. It’s a quad core ARM A72 running at 1.5Ghz with 4GB of RAM and native 1Gbps ethernet. This means that according to our benchmarks (PHP 7.3 and WordPress) it’s about 2.5x the speed of the 3B+, thanks to the much faster core design and slight clock speed boost. The downside is that it uses more power. Idle power consumption is up slightly to about 3W, peak is now around 7W, up from 5W. It has some improved video features too and USB3.

We obtained an early sample and benchmarked it running the Raspberry Pi website. We used the main blog, which hosts the blog, and has historically been the most CPU-intensive site to provide. We now see complete page generation in about 0.8s, compared to 2.1s for the 3B+. Obviously in normal operation, most pages are served from a cache, and so the typical end user experience is much faster.

We were really excited by the Pi 4 and wanted to have them available in our cloud for launch day. Unfortunately, Eben had some bad news for us: netboot on the Pi 4 is only going to be added in a future firmware update. Netboot is critical to the operation of our cloud, as it prevents customers from bricking the servers. Our dreams were shattered.

Our standard Pi Cloud unit consists of 6x9x2 blocks of Pi 3B servers connected to PoE switches with just one wire per server. They all net boot and are controlled through our control panel and API for customer use. Since the lack of netboot means we couldn’t just drop the Pi 4 in as a faster version at this time, we went back to the lab and we built an alpha Pi 4 Cloud on a smaller scale: 18 Pi 4s that Raspberry Pi have very generously given to us, all connected with gigabit ethernet so we can try out the 2.5x faster CPUs, 3x faster Network and 4x RAM capacity. We deployed this to our Sovereign House data centre where it connects to our core network.

In full production, we’ll have six racks of Pi 4 stacked back to back.

What we needed then was a test application. We suggested running the main Raspberry Pi website, as we once did with the Pi 3. But with over twice the horsepower per machine we thought we’d dream bigger. How about hosting the Raspberry Pi website on the Raspberry Pi 4, on the Raspberry Pi 4 launch day?

We’ve set up 14 Pi 4s for PHP processing for the main website (56 cores, 56GB RAM), two for static file serving (8 cores, 8GB RAM) and two for memcached (8 cores / 8GB RAM). Late on Friday night we started moving production traffic from the existing virtual machines to the Pi 4 cluster, completing the move shortly after midnight. Every page from the blog after Sat 22nd June has been generated on a Raspberry Pi 4.

Unfortunately, this configuration isn’t yet ready to become the standard, production environment for the Raspberry Pi website. As noted above, the Pi 4s don’t yet support netboot, and so these ones have local SD card storage rather than netboot and network file storage. This means they can’t be remotely re-imaged and have comparatively unreliable storage. The configuration is also only deployed in a single data centre with all servers on a single switch, whereas in normal usage the Raspberry Pi website is simultaneously hosted in two different data centres for redundancy.

To make things more nerve wracking, Pi 4 requires Debian Buster which is a pre-release version of the operating system (full release July 6th). So it’s a cluster of brand new hardware, with a pre-release operating system and a single point of failure. We very strongly advise our customers not to use this for a mission critical super high profile website under-going the most significant production launch in their history. That really isn’t a very good idea.

We once advised Eben that Raspberry Pi probably wouldn’t sell very many computers. He didn’t listen to us then either.

We haven’t moved the entire stack to the Pi 4. The front-end load balancers, download and apt servers are still on non-Pi hardware, split across three data centres (two in London, one in Amsterdam). The Pi 4 hardware looks well-suited to taking over these roles too, although we’ve kept the current arrangement for now, as it’s well tested and allows us to switch back to non-Pi 4 back-ends quickly if needed.

We haven’t moved the databases to the Pi 4 yet either. We’re not going to do that until we can have nice reliable mirrored storage on enterprise SSDs with high write reliability and long write lifetimes attached to the Pis.

Where do we go from here?

Once netboot on Pi 4 is available, we’ll be adding 4 core A72 / 4GB servers to our Pi Cloud, at a slightly higher price than the existing Pi 3 servers, reflecting the higher hardware and power costs. We are also planning to investigate virtualisation as 1 core / 1GB Raspberry Pi VMs may be of interest to existing Pi3 users. 64 bit kernel support and potentially a 64 bit userland would also now be worth investigating.

If you like the idea of Pi 4 in the cloud, a Pi 4 VM in the cloud or 64 bit ARM in the cloud, tell us your plans at

Out standing in a field

May 24th, 2019 by

Mythic Beasts: out standing in a field

Last year the Cambridge Beer Festival tried accepting payments by contactless cards. This didn’t work very well. They built a wireless LAN around the bar so that their card payment machines could process transactions. This went to an uplink that was a Raspberry Pi with a 4G dongle attached, this wasn’t really reliable enough for a full payment system, but worked as a proof of concept.

To improve things for this year we had a conversation with some friends at the recently incorporated Light Blue Fibre Ltd and between us were able to arrange for Jesus Green to have a fibre and an interlink to Mythic Beasts. As this is a prototype, we’re running below optimum speeds so we’ve delivered a relatively leisurely 1Gbps to the festival. The access points will happily deliver 150Mbps symmetric at any point on the bar if you have a quick enough wifi card in your laptop. We’ve still got the 3G uplink enabled as a backup just in-case someone slices the fibre.

If my phone had an Ethernet socket we’d be ten times as fast.

This year the plan was to restrict things to the tills and the administration network. However, being techies in a beer festival there is a tiny chance we may have been slightly drunk and enabled public wifi with a 100Mbps rate limit. This works well around the bar but there’s nowhere near enough access points to cover the outdoors and the onsite router is limited to 500 devices. It’s not yet production ready for 5,000 beer-drinking visitors, but we have a beer mat and a pencil and we’re sketching out ideas for next year.

Mythic Beasts gaan naar Nederland

February 20th, 2019 by

The art warehouses in Amsterdam look much prettier than the data warehouses.

Back in July 2018, Mythic Beasts acquired Bhost, giving us additional virtual machine (VM) clusters in London, Amsterdam and California.

Today we’re pleased to announce that we’ve deployed a substantial new VM cloud to Amsterdam, running our own VM platform. Virtual machines in Amsterdam are available to purchase immediately through our website in sizes from 1GB/1vCPU to 160GB/12vCPUs, and with both SSD and spinning rust disk options. Server management and backup options are also available.

Thanks to Brexit-related regulatory uncertainty, some of our existing clients informed us that they must be hosted outside of the UK before 29th March. Deploying capacity on our own platform in Amsterdam means that we can migrate virtual servers directly to the new location.

Once we’ve dealt with the immediate Brexit-driven server moves, we’ll be looking at migrating former-Bhost VMs into this new cloud, giving a significant performance boost in the process.

Deploying the Amsterdam VM cloud is a significant milestone in the integration of the Bhost infrastructure into our own. The integration provides improved performance and redundancy for both Mythic Beasts and Bhost customers whilst simultaneously cutting our operating costs. In preparation for this, we completed upgrades to our core network last October. The existing fibre ring around our three main London sites, which is currently lit at 50Gbps, is now complemented by a 10Gbps ring around London (HEX) ⟺ Cambridge ⟺ Amsterdam ⟺ London (MER). This replaces the old 2x1Gbps connectivity from Cambridge to London with diverse 10Gbps feeds to London and Amsterdam. Our network has gained an additional 10Gbps transit in Amsterdam (NTT) and we are also now connected on the Amsterdam Internet Exchange (AMS-IX).

On a trip to deploy new routers, Pete even managed a tour of the city on foot in just over three hours.

Primary reasons for choosing Amsterdam include being a flat country that’s easy to cycle around, a remarkably nice overnight ferry journey and superb boy bands asking us to stay. Secondary reasons are all boring such as a well developed market for data centres and internet transit, a world class internet exchange and remarkably few insane British politicians. We’re looking forward to the first Anglo-Dutch cricket match.

libssh emergency update

October 17th, 2018 by

An attack so simple my cat could get root on your server.

Managed customers of Mythic Beasts with libssh installed will have just received a notification that we updated it without warning or testing.

This is obviously bad practice, so what were we thinking?

A security advisory for libssh has just come out which is very bad. To paraphrase,

libssh -> hello new user
user -> can I have a root shell
libssh -> can you authenticate?
user -> yes but I'm not going to
libssh -> okay, have a root shell

This is completely secure, unless the client is prepared to lie in order to exploit your system. In the late 1990s some of our founders might have once exploited an online quiz in exactly the same way to get perfect scores. Don’t trust the client.

In our risk analysis, the risk of breakage to a customer site though a botched patch is vastly lower than giving an attacker a root shell, which is why we pushed an emergency update within a few hours of updated packages being available.

If this is the first you’ve heard about the issue, we suggest you’d benefit from our Managed Services

Toby Goodwin (1968-2018)

October 5th, 2018 by

At Mythic Beasts we rotate staff members around different roles. This is to protect the company from the unlikely event that a staff member is abducted by aliens and someone else has to take over at short notice.

With great sadness we have to report that Toby Goodwin, our first full time employee was not abducted by aliens. Much worse, he had an undiagnosed asymptomatic heart problem and passed away unexpectedly and painlessly last week.

Back in 2010 Toby had been running a bookshop in Cambridge with a quirky and eclectic selection of books. That business had come to an end and Toby was wondering about dusting off his UNIX skills and looking for work. At the same time Mythic Beasts had grown too large for the two then-active founders to effectively keep up and after an interview over a beer in the Devonshire Arms, Toby joined Mythic Beasts.

We didn’t initially realise how lucky we were because Toby had the perfect blend of skills. An experienced UNIX hacker from his days at Cygwin, he quickly figured out most of the technical operations to keep Mythic running. Meanwhile his experience at the bookshop gave him incredible patience and empathy for confused customers. He took it on himself to continuously improve our operations introducing radical new ideas like helper scripts having consistent names to make them easy to find, continuous integration and automated testing of our control panel.

Toby implemented the bulk of our managed server update system. When he started, we had tens of managed customers and updating packages was starting to become time consuming. Gradually this became a highly reliable and flexible system which means we can audit and update thousands of servers quickly and efficiently, whilst correctly notifying every affected customer in a timely fashion. Toby was always modest about his achievements and never suffered from being defensive about his code. When our summer students discovered a significant security flaw in a piece of configuration, he congratulated them and worked with them to resolve it quickly.

After working with us for a few years in Cambridge, Toby met Heather and moved with her to her native Scotland where they married and brought into the world a highly reliable early morning alarm clock called Zachary. Toby would regularly work early in the morning before taking some time out to deliver Zachary to nursery or work with him on significant structural engineering projects.


In addition to being a skilled software developer, Toby was also a brilliant railway engineer in the face of feline opposition.

Goodnight Toby. We’ll miss you.