Why Discord links stop working as a levelurl

What changed

Discord added expiring links to stop its CDN being used to distribute malware. Attachment links now end with three extra parameters:

https://cdn.discordapp.com/attachments/…/your-map.map?ex=…&is=…&hm=…

ex is when the link expires, is when it was issued, and hm is a signature over the two. Once the expiry passes, the link is refused. Inside the Discord app you never notice, because Discord quietly refreshes links as you scroll. The moment you copy one out, the clock is running.

Why it breaks a Rust server

Your server downloads the map once at startup, and so does every player when they join. A Discord link usually passes the first test and fails the second:

• You set the link, restart, and the map loads. Everything looks fine.
• A day later, new players cannot join. The people already on the server carry on as normal, so the reports trickle in slowly.
• Your next restart fails too, because the server cannot fetch the map any more.

It is a nasty failure because it looks like the server is fine, right up until it empties out.

What to use instead

Anything that serves the file itself with a link that does not expire: your own web server, or a host built for it. Maps onRustMapCDN are free, up to 200 MB, and their links stay up for 90 days from upload with the expiry date shown in your dashboard, so it is never a surprise.

Moving over takes a minute:

1. Download the .map file from Discord while the link still works.
2. Upload it and copy the new link.
3. Change server.levelurl and restart. Full steps: adding a custom map to your server.