# Http 3 does not work as expected on tcp backend service

**URL:** <https://community.traefik.io/t/http-3-does-not-work-as-expected-on-tcp-backend-service/23425>\
**Category:** Traefik v3 (latest)\
**Tags:** udp, tcp, docker\
**Created:** [July 1, 2024, 8:14pm UTC](https://community.traefik.io/t/http-3-does-not-work-as-expected-on-tcp-backend-service/23425 "2024-07-01T20:14:59Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![renothing](https://sea2.discourse-cdn.com/flex020/user_avatar/community.traefik.io/renothing/32/5534_2.png) [@renothing](https://community.traefik.io/u/renothing)\
**Post date:** [July 1, 2024, 8:14pm UTC](https://community.traefik.io/t/http-3-does-not-work-as-expected-on-tcp-backend-service/23425/1 "2024-07-01T20:14:59Z")

</div>

My traefik runs on docker, it is used as my container service proxy  
there are two types http service running on backend containers

A: normal nginx container which serve local HTTP services  
B: several nginx containers running TCP stream proxy which proxy remote HTTPS service(like github etc)

there are two traefik enpoints at port 80 and 443.

What we expect is that both local HTTP and proxy HTTP service through TCP SNI proxy can run normally

### What did you see instead?

when I disable http 3, all jobs work fine as my expected. both service A and service B will be routed correctly.

but then when I enable http3,

only type A services work fine and http3 also work correctly.

all traffic to type B service will return 404 directly.  
for example visit [https://www.bbb.com](https://www.bbb.com) will return 404

### What version of Traefik are you using?

```auto
Version: 3.0.3
Codename: beaufort
Go version: go1.22.4
Built: 2024-06-18T14:31:20Z
OS/Arch: linux/amd64

```

### What is your environment & configuration?

here are seagment of my traefik config

```yaml
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--entrypoints.web.address=:80"
      - "--entrypoints.web.reuseport=true"
      - "--entrypoints.web.http.redirections.entrypoint.to=websecure"
      - "--entrypoints.web.http.redirections.entrypoint.scheme=https"
      - "--entrypoints.websecure.address=:443"
      - "--entrypoints.websecure.reuseport=true"
      - "--entrypoints.websecure.asdefault=true"
      - "--entrypoints.websecure.http.encodequerysemicolons=true"
     - "--entrypoints.websecure.http3=true"
      - "--entrypoints.websecure.http3.advertisedport=443"
      - "--entrypoints.websecure.forwardedheaders.insecure=true"
      .....

```

here is my type A service config seagment

```yaml
    labels:
      traefik.enable: "true"
      traefik.http.routers.fakesite.entrypoints: "websecure"
      traefik.http.routers.fakesite.rule: 'HostRegexp(`(?i)^img(1|2|3)?\.aaa\.net$`)'
      traefik.http.routers.fakesite.service: "fakesite"
      traefik.http.services.fakesite.loadbalancer.server.port: 80
      traefik.http.routers.fakesite.tls: "true"
      traefik.http.routers.fakesite.tls.certresolver: "le"
      ...

```

here is my type B service config seagment

```yaml
    labels:
      traefik.enable: "true"
      traefik.tcp.routers.cfproxy.entrypoints: "websecure"
      traefik.tcp.routers.cfproxy.rule: 'HostSNIRegexp(`(?i)^((.+\.)?bbb.com|(.+\.)?github\.com)$`)'
      traefik.tcp.routers.cfproxy.service: "cfproxy"
      traefik.tcp.services.cfproxy.loadbalancer.server.port: 4432
      traefik.tcp.routers.cfproxy.tls: "true"
      traefik.tcp.routers.cfproxy.tls.passthrough: "true"
      ......

```

### If applicable, please paste the log output in DEBUG level

172.19.0.1 - - [29/Jun/2024:10:20:47 +0000] "GET / HTTP/3.0" 404 19 "-" "-" 1 "-" "-" 0ms  
172.19.0.1 - - [29/Jun/2024:10:20:47 +0000] "GET /favicon.ico HTTP/3.0" 404 19 "-" "-" 2 "-" "-" 0ms

### Question

Is it because http3 runs on udp, and udp does not implement HostSNIRegexp?