TLDR:
- I have to enter the IP instead of the hostname in NPM because I get random 502s in Docker Web Apps
curl -6 <dockerapp>fails, butcurl -4 <dockerapp>works- Otherwise IPv6 is enabled and works everywhere else including Docker-Containers except when they go through NPM or when using curl without NPM, because the Networks prefers IPv6
- I’m on
Version: 25.04.1
So my case is:
- I have an Affine docker container that works generally fine in the browser with
<truenashost>:30169 - When accessing it through Nginx Proxy Manager I noticed a lot of errors
I thought it was my NPM configurations fault, but then I tried the following commands from any device in my network:
curl -6 -vk http://<truenashost>:30169:
* Host <truenashost>:30169 was resolved.
* IPv6: 2a02:...:73c2, fd30:...:73c2
* IPv4: (none)
* Trying [2a02:...:73c2]:30169...
* connect to 2a02:...:73c2 port 30169 from :: port 49423 failed: Connection refused
* Trying [fd30:...:73c2]:30169...
* connect to fd30:...:73c2 port 30169 from :: port 49429 failed: Connection refused
* Failed to connect to <truenashost>port 30169 after 4099 ms: Could not connect to server
* closing connection #0
curl: (7) Failed to connect to <truenashost>port 30169 after 4099 ms: Could not connect to server
curl -4 -vk http://<truenashost>:30169
<normal and expected html response>
So from what I can tell this seems to be a fundamental issue and not an NPM configuration issue, DNS issue or HTTPS issue.
I have a Fritz.Box with Native IPv6 and everything generally works.
I’m on version 25.04.1
This is from the TrueNAS Scale Host if that helps:
sudo docker network inspect bridge
[
{
"Name": "bridge",
"Id": ".....",
"Created": "2025-07-06T21:47:58.688103......",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": true,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "fdd0::/64"
},
{
"Subnet": "172.16.0.0/24",
"Gateway": "172.16.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {
"com.docker.network.bridge.default_bridge": "true",
"com.docker.network.bridge.enable_icc": "true",
"com.docker.network.bridge.enable_ip_masquerade": "true",
"com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
"com.docker.network.bridge.name": "docker0",
"com.docker.network.driver.mtu": "1500"
},
"Labels": {}
}
]
Also forcing Nginx Proxy Manager to use IPv4 by entering the IP instead of <truenashost> fixed the issue in the container for now.
Another container of qbittorrent that fails in the same way as for curl -6 generally seems to work with IPv6 as well:
(N) 2025-06-25T10:41:07 - WebAPI login success. IP: 2a02:...:f8ba
(N) 2025-06-25T10:46:45 - WebUI: HTTPS setup successful
(N) 2025-06-25T10:46:49 - WebAPI login success. IP: 2a02:...:f8ba
(N) 2025-06-25T10:49:18 - WebUI: HTTPS setup successful
While OpenWebUi also constantly fails with such errors when accessed over NPM, but also fails for curl -6:
index.ts:60
POST https://llm.apps.<truenashost>/api/v1/auths/admin/config 502 (Bad Gateway)
p @ index.ts:60
A @ General.svelte:81
await in A
te @ General.svelte:116
index.ts:73
SyntaxError: Unexpected token '<', "<html>
<h"... is not valid JSON
(anonymous) @ index.ts:73
Promise.catch
p @ index.ts:72
A @ General.svelte:81
await in A
te @ General.svelte:116
From what I understand containers also bind on IPv4 and IPv6
Can someone point me in the right direction or knows this issue?