Unable to set an ipv6 address for a service

[TLINDEN]

Overview of the Issue

I want to create a service with nomad+consul on an ipv6-only machine, which doesn't work.

---

Reproduction Steps

According to the documentation, one needs to add this to a service config in order to assign an ipv6 to the public interface of a system:

tagged_addresses {
  wan_ipv6 = "..."
}

When I just add an ipv6 address:

tagged_addresses {
  wan_ipv6 = "2a01:4f8:c2c:cd3c:fefe::beef"
}

Then the following error occurs:

2026-01-22T07:40:31.578+0100 [ERROR] client.alloc_runner: prerun failed: alloc_id=b93350ec-8196-398f-7d32-db946efddc87 error="pre-run hook \"group_services\" failed: error parsing address \"2a01:4f8:c2c:cd3c:fefe::beef\": address 2a01:4f8:c2c:cd3c:fefe::beef: too many colons in address

Then I looked up the code and saw, that it calls net.SplitHostPort() for whatever strange reason, which expects for ipv6 something like [ip]:port. Since the port cannot really be a part of the wan_ipv6 field, I tried:

tagged_addresses {
  wan_ipv6 = "[2a01:4f8:c2c:cd3c:fefe::beef]"
}

which yields this error:

2026-01-22T07:47:24.279+0100 [INFO]  client.alloc_runner.task_runner: Task event: alloc_id=f3a7eecb-9a3b-1904-ec4a-950dec17db91 task=nginx-task type="Setup Failure" msg="failed to setup alloc: pre-run hook \"group_services\" failed: error parsing address \"[2a01:4f8:c2c:cd3c:fefe::beef]\": not an IP address" failed=true

Ok, so the port seems to be required, then I tried:

tagged_addresses {
  wan_ipv6 = "[2a01:4f8:c2c:cd3c:fefe::beef]:80"
}

Now the service comes up without any errors, it's also reachable via its dynamic ipv6 address, but not from the one I specified.

The address is also not configured on the machine, which is something I'd expect from Consul. What use would it be for otherwise? However, I tried to add an alias to the public interface like this:

oot@podmaster: # ifconfig bridge0 inet6 2a01:4f8:c2c:cd3c:fefe::beef/128 alias

root@podmaster: # ifconfig bridge0
bridge0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1500
        options=0
        ether 92:00:06:fa:8f:0c
        inet 10.89.1.1 netmask 0xffffff00 broadcast 10.89.1.255
        inet6 2a01:4f8:c2c:cd3c::1 prefixlen 80
        inet6 fe80::9000:6ff:fefa:8f0c%bridge0 prefixlen 64 scopeid 0x3
        inet6 2a01:4f8:c2c:cd3c:fefe::1 prefixlen 80
        inet6 2a01:4f8:c2c:cd3c:fefe::beef prefixlen 128
[..]

But this didn't make any difference.

Unfortunately it is also impossible to inspect running services. One can only list services but not get any details about them.

Consul info for both Client and Server

# consul info
agent:
        check_monitors = 0
        check_ttls = 0
        checks = 5
        services = 5
build:
        prerelease = 
        revision = 3261d11
        version = 1.21.5
        version_metadata = 
consul:
        acl = enabled
        bootstrap = true
        known_datacenters = 1
        leader = true
        leader_addr = [2a01:4f8:c2c:cd3c::1]:8300
        server = true
raft:
        applied_index = 6407
        commit_index = 6407
        fsm_pending = 0
        last_contact = 0
        last_log_index = 6407
        last_log_term = 4
        last_snapshot_index = 0
        last_snapshot_term = 0
        latest_configuration = [{Suffrage:Voter ID:7b9ad78f-d64b-c73f-9d0b-bb7631fb05e3 Address:[2a01:4f8:c2c:cd3c::1]:8300}]
        latest_configuration_index = 0
        num_peers = 0
        protocol_version = 3
        protocol_version_max = 3
        protocol_version_min = 0
        snapshot_version_max = 1
        snapshot_version_min = 0
        state = Leader
        term = 4
runtime:
        arch = amd64
        cpu_count = 2
        goroutines = 197
        max_procs = 2
        os = freebsd
        version = go1.25.0
serf_lan:
        coordinate_resets = 0
        encrypted = false
        event_queue = 1
        event_time = 4
        failed = 0
        health_score = 0
        intent_queue = 0
        left = 0
        member_time = 1
        members = 1
        query_queue = 0
        query_time = 1
serf_wan:
        coordinate_resets = 0
        encrypted = false
        event_queue = 0
        event_time = 1
        failed = 0
        health_score = 0
        intent_queue = 0
        left = 0
        member_time = 1
        members = 1
        query_queue = 0
        query_time = 1

# config
datacenter = "dc1"
data_dir = "/var/db/consul"
bind_addr= "2a01:4f8:c2c:cd3c::1"
acl {
  enabled = true
  default_policy = "deny"
}
server = true
bootstrap_expect = 1

That's all I have, theres just 1 instance on 1 machine.

Operating system and Environment details

                 OS: FreeBSD 14.3-RELEASE-p7
             Consul: Consul v1.21.5, Revision 3261d11, Build Date 2025-09-25T08:51:49Z
              Nomad: v1.11.1
nomad-driver-podman: 0.6.3_3

I also attached the spec of the running podman container.

2c8fc20ba5e2.json