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Comment by kmm | Hacker News Reader

I understand there are API limitations, but isn't 15 minutes a lot for an object that orbits around the entire Earth in 90 minutes? On average you're going to be off by about a twelfth of the circumference of the Earth, or roughly the distance between Lisbon and Istanbul

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Yes. As I say in the post, you shouldn't use this for docking operations.

If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.

> As I say in the post, you shouldn't use this for docking operations.

Brilliant. :-D

You totally could use it for docking. A real ISS docking manoeuvre takes several hours. Orbits are very predictable and I'm quite confident that the error you'd get projecting your orbit 15min into the future would be good enough to get within close radar range for the final approach. In fact you probably could do it, even if your spavecraft doesnt have DNS at all, and you have to do the DNS resolve from a ground laptop before you board it. Soyez can dock within 3 hours of lauch. Orbits are very predictable in this timeframe.

I shall make the suggestion to NASA that they start using this ;-)

Sure they're predictable, but since you don't get the exact timestamp for those expired coordinates, it's still useless.

Oh, and accuracy is shit anyway (altitude is rounded to 10m)

If there's no timestamp, all you know is a Lat/Long that was accurate sometime in the last 15 minutes (or more, "best effort basis"). But you don't know when, and you don't know the altitude. That's gonna make using that information for docking...difficult.

> If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.

Why not setup your own name server?

This is the correct way - dynamic DNS servers frequently have very low TTLs set.

Serving DNS yourself is such an incredibly small bandwidth impact - most of the packets are in the 10's to 100's of bytes - and authoritative DNS servers do not do a lot of processing, just send back RR's from zones which are read at boot time, or updated in an in-memory database.

I couldn't be bothered to set up a DNS server for such an ephemeral joke.

But I would love to read your blog post about setting one up and what you learned.

Coredns is so simple to configure and is a barebones container deployment.

Cool! Please set it up and write a blog post about it.

I'm not being snarky. I've never set up something like that and I'm sure lots of people would be happy to ready about it.

hi, i haven’t made a video but i have some stuff set up for it:

https://youtu.be/AJ2Q12vYojY https://youtu.be/GoPWuJR6Npc

and i host https://dnsroleplay.club which lets you answer real people’s dns requests, there should be links to the github for how it’s done

mailinabox.email. Just use the DNS part and not worry about mx if you want something fairly simple

Unless you send any reply that is significantly largest than the request, like this one, and then you can be exploited to DDoS someone else via an amplification attack. https://www.cloudflare.com/learning/ddos/dns-amplification-d...

zdw mentioned an "authoritative" server, i.e. a content DNS server. CloudFlare is not talking about content DNS servers there. It cannot decide from paragraph to paragraph what it is calling the DNS servers that it is talking about, but it is talking about proxy DNS servers, that respond with the actual grunt work of query resolution done.

People like me have been recommending not running public proxy DNS servers for the entirety of the 21st century thus far, and the world has taken some notice, although more work is required, world!

* https://jdebp.uk/FGA/proxy-server-ip-addresses.html

In any case, ANY queries do not work nearly as well for amplification attacks as they used to. Many people have read RFC 8482. I, for example, changed all of the DNS servers in djbwares to respond to ANY queries per RFC 8482 back in March 2019.

The task at hand in this discussion only involves running a content DNS server, serving LOC records from some file/database or other.

CF does say "dns resolvers" right in the lead

> If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.

Does Cloudflare not allow this?

I'd say the API can take up to half a minute to propagate, so API updates every minute is running up against their own performance. If you're a free customer, they may block you after a while, but first they'd have to notice you, and I doubt one update per minute would bother them.

It’s quite easy to run your own DNS server — I've found it a worthwhile exercise. Of course, you’ll need a server to run it on.

Cloudflare does this with an API. If you have any money, I'd suggest dnsimple.com instead.

> As I say in the post, you shouldn't use this for docking operations

Remember people, DNS stands for "Definitely Not for Space-docking"

or "Docking Not Supported"

At orbital speed of ~7.66 km/s, the ISS travels approximately 6,900 km during a 15-minute interval, which is indeed significant for precise location tracking.

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