UDP not being proxied over cloudflared with routed ips

Is anyone also having issues with UDP over cloudflared?

I have a cloudflared tunnel which routes some internal networks for both TCP and UDP.

I use a few apps, such as mosh, that need UDP and they suddenly stopped working.

I also queried my DNS that’s on the other side of the tunnel and it gets no response.

So I believe this option is not working:


UDP isn’t enabled by default.

Anyone having the same issues?

UDP isn’t supported over cloudflared. Supported Protocols

This setting is not for tunnels.

UDP isn’t supported over cloudflared. Supported Protocols

That documentation is out of date.

https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/private-net/private-hostnames-ips/

This setting is not for tunnels.

This setting is exactly for that. Thanks for your answer though.

2022-07-20T03:16:00Z

I solved it. Here’s the solution for anyone facing the same issue:

TL;DR: Add protocol: quic to your config.yml and restart cloudflared.

After reading the documentation I realized I was missing adding quic as the default transportation for cloudflared. Checking the logs it looks like cloudflared did try quic as the default transportation but it was somehow switching to http2:

{"level":"info","connIndex":0,"time":"2022-06-25T03:13:50Z","message":"Retrying connection in up to 32s seconds"}
{"level":"info","connIndex":0,"time":"2022-06-25T03:14:13Z","message":"Switching to fallback protocol http2"}
{"level":"debug","connIndex":0,"time":"2022-06-25T03:14:13Z","message":"Connecting via http2"}

So by adding protocol: quic and restarting the cloudflared UDP protocol is back working between WARP and my network segments tunneled through cloudflared.

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Just as a reference for others, make sure to go through this checklist: https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/private-net/private-hostnames-ips/#troubleshooting

The 2nd item would have helped here figure this out sooner.

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Also, thanks for pointing out the outdated documentation. We’ll get a fix up :+1:

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