Also as a _long_ list of other specialist TLS endpoint configurations if you're interested, which can be arbitrarily combined, see https://testserver.host/#tls-endpoints.

That gives neat tricks like https://tls-v1-2--expired--incomplete-chain--http2.testserve...: only accepts TLS 1.2, then sends an expired certificate but fails to send the intermediate cert for the chain (so the client must infer it) and then negotiates HTTP/2 for the connection on top. Fun!

I caught it in review but thousands of others won't.

That ship has sailed I would say.

[1]: https://captive.apple.com/

As an example, depending on "man -w" not outputting anything to stderr: https://unix.stackexchange.com/questions/405783/why-does-man...

Would you settle for any old static page served by Cloudflare? For instance, example.com? https://bgp.tools/dns/example.com

Just before COVID, a random unidentifiable person reported that 1.1.1.1 saw 60Mb/s of ICMP echo traffic. When APNIC first experimented with making it a valid network almost a decade before that, it was being sent 50Mb/s of general IP traffic. Amusingly, a side-effect of what CloudFlare has done is that it has stopped all of that traffic leaving the edges of the Internet, and funnelling in to one big central place.

There are those who remember the risks of 'just use 1.1.1.1' and how the people who did that used be characterized as 'bad Internet citizens'. The ServerFault answer (q.v.) is from 2011.

* https://labs.ripe.net/author/franz/pollution-in-18/

* https://news.ycombinator.com/item?id=19335833

* https://serverfault.com/a/339782

Likely for good reason, even back then there would have bound to be lots of misconfigured endpoints trying to access 1.1.1.1, so just blocking it at the earliest point possible kept at lot of the annoyance away. Nowadays, it’s an anycast address, so it’s slightly less bad.

But for me, old habits die hard.

Pinging such an address is inherently a troublesome practice. This address, like many public DNS servers (resolvers as well as root and authoritative ones), uses "anycast" routing methodology.

https://en.wikipedia.org/wiki/Anycast

Pinging an anycast address will yield a cornucopia of different results. Of course, people who naïvely "ping" a recognizable or easy-to-type IPv4 address get what they deserve, especially when they enshrine it into software, unit tests, or the LLM coughs up such tokens on their behalf.

Fundamentally, the question is "what do you really want to test?" by pinging a particular IPv4? Do you want to test Layer 3 connectivity? Test your ISP's backbone and connectivity? Test only your upstream router? Test the existence of ICMP in your stack and theirs?

... the possibilities are endless. Your router can do anything. Ping zombo.com.

I kinda expected this to be Ford Model T "Any color the customer wants, as long as it’s black" joke.

McCarthy of DebugBear clearly noticed this admonition and perhaps the mistake as well, because they have carefully highlighted "example.com" without linking to it, although they apparently have visited the site in order to copy and cite screenshots and unpack the CSS, and describe an extensive history of it.

(I actually tried the select, share [sic], open in browser route, but for some reason I only saw opera as an option, not chrome, the browser I actually use for everything. Links still rule.)

0

```

var B = document.body, P, p; B.children[0].insertAdjacentHTML("afterend", "<p lang=ar dir=rtl>هذا النطاق مُخصص للاستخدام في أمثلة التوثيق دون الحاجة إلى إذن. هذه ليست خدمة، يُرجى تجنب الاعتماد عليها لأغراض الاختبار والمراقبة.</p><p lang=zh>该域名仅用于文档示例，无需获得许可。这并非一项服务，请勿将其用于测试和监控目的。</p><p lang=fr>L’usage de ce domaine est réservé à des exemples de documentation, sans autorisation préalable. Il ne s’agit pas d’un service ; son utilisation à des fins de test ou de surveillance est à éviter.</p><p lang=ru>Данный домен предназначен для использования в примерах документации без необходимости получения предварительного разрешения. Это не сервис; не рекомендуется его использование для тестирования и мониторинга.</p><p lang=es>Este dominio está destinado al uso en ejemplos de documentación sin necesidad de permiso. Esto no es un servicio; evitar utilizarlo para realizar pruebas o monitoreos.</p><a href=https://iana.org/help/example-domains>Learn more</a>"); P = [...B.querySelectorAll("p")]; P[0].lang = "en"; navigator.languages.some(l => p = P.find(p => p.lang == l.split("-")[0])); p = p || P[0]; B.prepend(p); B.insertAdjacentHTML("afterbegin", '<style>svg{display:block;margin:-2.75em auto 0;opacity:.55}p+p{font-size:.875em;opacity:.6}</style><svg viewBox=0,0,20,20 width=44 height=44 fill=currentColor aria-hidden=true><path fill=none stroke=currentColor stroke-width=1.3 stroke-linejoin=round d="M6 4H3v12q4 0 7 1.5-1-3.5-4-4.5V2q3.5 1 4 3v12.5q3-1.5 7-1.5V4q-4.5 0-7 1"/><g transform=rotate(-6,13.6,8.3)><path id=q d="M11.5 6.6h1.8v1.8l-1 1.6-.6-.3.8-1.3h-1z"/><use href=#q x=2.4 /></g></svg>')

```

1

```

<!doctype html> <html lang=en> <head> <meta charset=utf-8> <link rel=icon href=data:,> <meta name=viewport content="width=device-width,initial-scale=1"> <title>Example Domain</title> <style> html { color-scheme: light dark; background: light-dark(#eee,#222) }

            body {
                font: 16px/1.6 system-ui,sans-serif;
                max-width: 26em;
                margin: auto;
                padding: 25vh 2em 2em;
                text-align: center
            }
        </style>
    </head>
    <body>
        <p>This domain is for use in documentation examples without needing permission. This is not a service; avoid relying on it for testing and monitoring purposes.</p>
        <script src=/s.js></script>
    </body>

```

Are you perhaps on an untrusted network which is spoofing that url to make it redirect somewhere else?

The issue with example.com is this statement:

> This domain is for use in documentation examples without needing permission. This is not a service; avoid relying on it for testing and monitoring purposes.

The problem is that, disclaimer or not, if a website provides a useful utility, people will use it as a service.

If example.com breaks, IANA can reasonably say it was never intended to be stable. But that does not change the fact that people will use it for testing and monitoring.

What we do is adopt legacy services whose maintainers can no longer afford, want, or have the resources to maintain them, and invest in keeping them running reliably.

0: https://blog.cloudflare.com/monetization-gateway-beta/

> As it tends to be heavily trafficked, the overall bandwidth is a key consideration