X-Clacks-Overhead

My website returns a random person in a list for every X-Clacks-Overhead response header: https://github.com/Xe/site/blob/877872b4d7db92b602683ecb4e99...

I figured this was one of the best ways to do it. That way I'm letting people that were significant to me live on forever, one random HTTP response header at a time.

  $ curl https://xeiaso.net --head | grep clacks
  x-clacks-overhead: GNU Satoru Iwata

The thing that struck me about "GNU John Dearheart" was how it feels like it _really_ deeply captures hacker culture, like Pterry wasn't just referencing the culture, but that he really got it. Which is remarkable, because he gave me that impression about many, many topics. Such a loss.

> In Terry Pratchett's science-fantasy Discworld series, "The Clacks" is a network infrastructure of Semaphore Towers, that operate in a similar fashion to telegraph - named "Clacks" because of the clicking sound the system makes as signals send.

Surely named "Clacks" because of the clacking sound the system makes.

It's been a while I heard about X-Clacks-Overhead. I added it to my own page to commemorate everyone I lost along the way. After reworking my site from a custom blog engine to plain web, I forgot to re-add the custom headers. Thanks for the reminder today!

There are also browser extensions, which show when a website broadcasts the "X-Clacks-Overhead" - header.

"We're obligated to inform you that this site uses cookies to do things like maintain your session and deliver personalised content. We also use third-party services from partners such as Google, who may also place cookies on your computer. Without cookies this site cannot function correctly. Please allow cookies from this website, otherwise features may not work."

Amusingly, that's not true. The only cookie they send is Google Analytics, which has zero value to the user. The site works fine with it blocked.

I tried making "real" clacks https://www.secretbatcave.co.uk/2025/03/12/gnu-terry-prachet...

I need more time and motivation to make a full network though.

Around 40,000 services on the Internet are currently including the header:

https://www.shodan.io/search/report?query=x-clacks-overhead+...

For some reason, a lot of honeypots are also using that header so I filtered those out. The number of services has slowly increased over time:

https://trends.shodan.io/search?query=x-clacks-overhead+-tag...

I always read this as something that would need to be done at a lower level, like forwarding some arbitrary information in a BGP update.

I love the idea! But to be true to the original, shouldn't the message be self-propagating?

> [...] header that can be transmitted from server to server [...]

How so? In HTTP, there's always one client and one server. Am I missing some way to make this sticky or self-propagating, e.g. browsers or other clients that will cache received headers and then send them to other servers?

I'm almost to this one in my read through! I'm excited to get to the "information age" arc

I try to add this to every project I work on.

I saw this header recently while profiling headers from feature phones. I think Opera Mini or another browser might’ve injected this header, which is odd because it’s meant to reduce bandwidth and sending it with each request goes against that

mozilla.org doesn't do it anymore:

    < HTTP/2 301
    < server: nginx
    < date: Sat, 05 Jul 2025 13:36:11 GMT
    < content-type: text/html
    < content-length: 162
    < location: https://www.mozilla.org/
    < strict-transport-security: max-age=60; includeSubDomains
    < x-backend-server: TS
    < cache-control: max-age=3600
    < via: 1.1 google
    < alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000

< x-clacks-overhead: GNU Terry Pratchett

Read Going Postal as a teen and absolutely loved it. But from today's perspective, I don't think this header as a general way of mourning is a good idea.

It took two very specific bits from the Discworld lore (the Clacks overhead and GNU) and made it in a general ritual of mourning. But not every techie is a Discworld fan, and the obscurity of the name would draw more attention to the Discworld lore than to the people being mourned.

The idea of sending a header to remember a tech person is a great one, but I think the name should be something neutral, or something that has some relation to the person and not a random fantasy reference.

(Reminds me a bit how the Berlin Pirate Party used to have a "Pony Time" paragraph in its charter, that members could use to request joint My Little Pony watching sessions on congresses. [1]

Seemed like a good idea at that time as Bronies were a new thing and there was a lot of overlap with Pirate Party members. But seems pretty cringeful looking back from today, and also a tad disrespectful towards those who tried to do real political work within that party. Disclaimer: Only got to know about that from the outside, so if their own stance on that is different, I take it back)

[1] https://youtube.com/watch?v=joyV8SqeN6k

great idea, just added it to my site

This is obviously the most important HTTP header, but HTTP is application-level, and clacks is a packet routing system.

Perhaps something like IPv6's Hop-by-Hop Options can be used to pass names with every packet?

Or, even better, we can use LoRa repeaters for something close to the actual clacks network.

If you happen to nominate or vote on the Hugo Awards, you may have seen this turn up.

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