[GH-ISSUE #3332] UDP packets not being forwarded

gitea-mirror commented

2026-05-05 13:43:19 -06:00

Owner

Originally created by @0xAl3xH on GitHub (Feb 24, 2023).
Original GitHub issue: https://github.com/fatedier/frp/issues/3332

Bug Description

What I've tried

Here is the frpc.ini configuration in what I will call the UDP_server

[udp-test]
type = udp
local_ip = 127.0.0.1
local_port = 9710
remote_port = 9710

After checking the dashboard to make sure the port is online:
Screen Shot 2023-02-24 at 1 38 24 PM

To test, I ran nc -lu 9710 on UDP_server and on my own machine, I ran echo "hello world" | nc -4 -v -u [FRP_server_IP] 9710 and nothing happened.

However, as a sanity check I set type = tcp and repeated the netcat test above with nc -l 9710 on the server and echo "hello world" | nc -4 -v [FRP_server_IP] 9710 on the client and I was able to recieve the message.

What I expected

I expected UDP forwarding to work as well.

What happened

TCP forwarding worked but UDP didn't

frpc Version

0.46.1

frps Version

0.46.1

System Architecture

linux/x86_64, macOS/arm64

Configurations

[udp-test]
type = udp
local_ip = 127.0.0.1
local_port = 9710
remote_port = 9710

and

[udp-test]
type = tcp
local_ip = 127.0.0.1
local_port = 9710
remote_port = 9710

Logs

No response

Steps to reproduce

Set the configurations
Run nc -lu 9710 on UDP_server
Run echo "hello world" | nc -4 -v -u [FRP_server_IP] 9710 on the client

Affected area

Docs
Installation
Performance and Scalability
Security
User Experience
Test and Release
Developer Infrastructure
Client Plugin
Server Plugin
Extensions
Others

Originally created by @0xAl3xH on GitHub (Feb 24, 2023). Original GitHub issue: https://github.com/fatedier/frp/issues/3332 ### Bug Description ### What I've tried Here is the `frpc.ini` configuration in what I will call the `UDP_server` ``` [udp-test] type = udp local_ip = 127.0.0.1 local_port = 9710 remote_port = 9710 ``` After checking the dashboard to make sure the port is online: <img width="862" alt="Screen Shot 2023-02-24 at 1 38 24 PM" src="https://user-images.githubusercontent.com/20210402/221298163-6dccdfe5-5533-43e1-ac2e-bbb8f1e31e2e.png"> To test, I ran `nc -lu 9710` on `UDP_server` and on my own machine, I ran `echo "hello world" | nc -4 -v -u [FRP_server_IP] 9710` and nothing happened. However, as a sanity check I set `type = tcp` and repeated the netcat test above with `nc -l 9710` on the server and `echo "hello world" | nc -4 -v [FRP_server_IP] 9710` on the client and I was able to recieve the message. ### What I expected I expected UDP forwarding to work as well. ### What happened TCP forwarding worked but UDP didn't ### frpc Version 0.46.1 ### frps Version 0.46.1 ### System Architecture linux/x86_64, macOS/arm64 ### Configurations [udp-test] type = udp local_ip = 127.0.0.1 local_port = 9710 remote_port = 9710 and [udp-test] type = tcp local_ip = 127.0.0.1 local_port = 9710 remote_port = 9710 ### Logs _No response_ ### Steps to reproduce 1. Set the configurations 2. Run `nc -lu 9710` on `UDP_server` 3. Run `echo "hello world" | nc -4 -v -u [FRP_server_IP] 9710` on the client ### Affected area - [X] Docs - [ ] Installation - [ ] Performance and Scalability - [ ] Security - [ ] User Experience - [ ] Test and Release - [ ] Developer Infrastructure - [X] Client Plugin - [ ] Server Plugin - [ ] Extensions - [X] Others

gitea-mirror

2026-05-05 13:43:19 -06:00

closed this issue
added the
lifecycle/stale
label

gitea-mirror commented

2026-05-05 13:43:22 -06:00

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Owner

@brostosjoined commented on GitHub (Mar 19, 2023):

Test with this see if the is udp or your configuration https://github.com/DKingAlpha/frp#all-ports-mapping

@brostosjoined commented on GitHub (Mar 19, 2023): Test with this see if the is udp or your configuration https://github.com/DKingAlpha/frp#all-ports-mapping

gitea-mirror commented

2026-05-05 13:43:22 -06:00

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Owner

@github-actions[bot] commented on GitHub (Apr 19, 2023):

Issues go stale after 30d of inactivity. Stale issues rot after an additional 7d of inactivity and eventually close.

@github-actions[bot] commented on GitHub (Apr 19, 2023): Issues go stale after 30d of inactivity. Stale issues rot after an additional 7d of inactivity and eventually close.

gitea-mirror commented

2026-05-05 13:43:23 -06:00

Author

Owner

@svinc33 commented on GitHub (Nov 21, 2024):

I'm having the same issue, it seems there's a weird issue with frp not forwarding UDP

@svinc33 commented on GitHub (Nov 21, 2024): I'm having the same issue, it seems there's a weird issue with frp not forwarding UDP

gitea-mirror referenced this issue

2026-05-05 14:45:17 -06:00

[PR #2672] [MERGED] remove authentication for healthz api #4608