ipv6 in apps with a dependency like postgres or other db

[dimagsv]

IPv6 isn't working in a WordPress Docker container. For example, running the following command in the container produces the following result

$ curl -vk https://ipv6.google.com

• Host ipv6.google.com:443 was resolved.
• IPv6: 2a00:1450:4025:804::71, 2a00:1450:4025:804::66, 2a00:1450:4025:804::65, 2a00:1450:4025:804::8a
• IPv4: (none)
• Trying [2a00:1450:4025:804::71]:443...
• Immediate connect fail for 2a00:1450:4025:804::71: Network is unreachable
• Trying [2a00:1450:4025:804::66]:443...
• Immediate connect fail for 2a00:1450:4025:804::66: Network is unreachable
• Trying [2a00:1450:4025:804::65]:443...
• Immediate connect fail for 2a00:1450:4025:804::65: Network is unreachable
• Trying [2a00:1450:4025:804::8a]:443...
• Immediate connect fail for 2a00:1450:4025:804::8a: Network is unreachable
• Failed to connect to ipv6.google.com port 443 after 12 ms: Could not connect to server
• closing connection #0
  curl: (7) Failed to connect to ipv6.google.com port 443 after 12 ms: Could not connect to server

It works correctly in containers of other applications, such as Open-speed-test.
I don't know if this is a problem with the application or the container.
On the host, in the file /mnt/.ix-apps/docker/containers/[identifier]/hosts, I found a difference between containers that do and don't support IPv6. The containers that support IPv6 have two lines like

172.16.3.2 90ae8352f620
fdd0:0:0:2::2 90ae8352f620

Containers that don't support IPv6 have only one of the two lines

172.16.4.3 98a4cba1cbfd

[stavros-k]

We don't really do anything special to add support for ipv6 on containers, ie it should work.

Do you have any other containers that use a dependency like postgres or other db that their ipv6 work?

[dimagsv]

I have another app with database - immich. IPv6 doesn't work in its container either.

[dimagsv]

Can you suggest me some more apps with db to check?

[stavros-k]

vaultwarden, gitea, forgejo

[dimagsv]

I've checked these apps. IPv6 does not work in their containers.
Ifconfig was installed in gitea. Here's the output.

/var/lib/gitea $ ifconfig
eth0      Link encap:Ethernet  HWaddr 02:78:C6:C7:5D:2F  
          inet addr:172.16.5.3  Bcast:172.16.5.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:4229 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4408 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1528933 (1.4 MiB)  TX bytes:2349557 (2.2 MiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:188 errors:0 dropped:0 overruns:0 frame:0
          TX packets:188 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:17633 (17.2 KiB)  TX bytes:17633 (17.2 KiB)

ifconfig from open-speed-test:

/ $ ifconfig
eth0      Link encap:Ethernet  HWaddr AA:68:35:78:5C:2A  
          inet addr:172.16.1.2  Bcast:172.16.1.255  Mask:255.255.255.0
          **inet6 addr: fe80::a868:35ff:fe78:5c2a/64 Scope:Link**
          **inet6 addr: fdd0:0:0:1::2/64 Scope:Global**
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:973 errors:0 dropped:0 overruns:0 frame:0
          TX packets:364 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:267267 (261.0 KiB)  TX bytes:103261 (100.8 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:45836 errors:0 dropped:0 overruns:0 frame:0
          TX packets:45836 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:51063093 (48.6 MiB)  TX bytes:51063093 (48.6 MiB)

It looks like this is a truenas issue and not a wordpress app issue.
My truenas version: 25.10.2.1 - Goldeye

[stavros-k]

I was afraid of that.
So the reason it happens only on apps that have dependencies is that for internal network we create we disable ipv6 due to an upstream bug

apps/library/2.3.3/networks.py

Lines 38 to 47 in df4adaf

	net_config = {
	"name": name,
	"external": False,
	"enable_ipv4": True,
	# We disable IPv6 for internal networks, because there is an upstream bug,
	# which any ipv6 network takes priority over ipv4 networks even with gw_priority set.
	# https://github.com/moby/moby/issues/51999
	"enable_ipv6": False,
	"labels": {"tn.network.internal": "true"},
	}

The actual upstream bug got resolved few days ago, but we need to wait for downstream docker to pick it up and bundle it on the next TrueNAS version.

As a workaround, I believe you can create a docker network (which afaik enables ipv6 by default) and attach it to the wordpress container.

DB <-> wordpress will continue to work using the internal network, but docker will enable ipv6 on wordpress.

[dimagsv]

Thank you. Adding a docker network helped me.
I'm leaving this issue open until a new version of TrueNAS with a fix is ​​released.