IPv6 on OpenWRT router behind my 5G Modem Router

Installing and Using OpenWrt Network and Wireless Configuration
1

Hello,

I have a 5G Modem Outdoor Router. It is a Suncomm Model O3 or also known as Hocell IM720. It has many other names and it is running a variant of OpenWRT by default.

I want to receive IPv6 on my router behind where actually all my devices are connected.

So what I did are these settings on the Modem Router:

image
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So far so good I receive something on my Dynalink Router:

image
image1010×285 18.5 KB

However I do not get any IPv6 connection outwards:
image

Does anybody have an idea what I am missing here? I have no clue but it would be really nice to have IPv6 setup.

I want to give as much information as possible. Maybe it helps when I say that I receive a public ipv4 from Vodafone (that is what they say, they gave me, IP starts with XXX.)

I have no information about the IPv6 part but I also receive an IPv6. When I connect the Modem Router directly to my PC, IPv6 test works!

I would be thankful for any help I get here.

Note:
I have a little bit of clue but I am not deep enough into networking to know everything. I hope I can learn something from that situation for future setups.

2

Disable NAT6 on the upstream device.
Make sure you get 2xxx: IPv6 address on OpenWrt wan, then configure IPv6 in relay mode.

3

If @AndrewZ 's excellent advice does not help, please connect to your OpenWRT device using ssh and copy the output of the following commands and post it here using the "Preformatted text </> " button:

Remember to redact keys, passwords, MAC addresses and any public IP addresses you may have:

ubus call system board
4

@AndrewZ This does not work unfortunately.

@egc Here is the output (nothing else came up):

{
        "kernel": "6.6.35",
        "hostname": "DL-WRX36",
        "system": "ARMv8 Processor rev 4",
        "model": "Dynalink DL-WRX36",
        "board_name": "dynalink,dl-wrx36",
        "rootfs_type": "squashfs",
        "release": {
                "distribution": "OpenWrt",
                "version": "SNAPSHOT",
                "revision": "r26800-843b51b26d",
                "target": "qualcommax/ipq807x",
                "description": "OpenWrt SNAPSHOT r26800-843b51b26d"
        }
}

I believe it has something to do with the ISP's CGNAT. They claim they gave me a public IP but maybe they only use something like a "workaround", it is not a true public ip. Is this a problem that eventually it can't pass that IP back and forth to another router?

5

Please show

ifstatus wan
ifstatus wan6
ifstatus lan
6

WAN:

{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "uptime": 34386,
        "l3_device": "wan",
        "proto": "static",
        "device": "wan",
        "updated": [
                "addresses",
                "routes"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "192.168.100.2",
                        "mask": 24
                }
        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "0.0.0.0",
                        "mask": 0,
                        "nexthop": "192.168.100.1",
                        "source": "0.0.0.0/0"
                }
        ],
        "dns-server": [
                "1.1.1.1",
                "1.0.0.1"
        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {

        }
}

LAN:

{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "uptime": 34678,
        "l3_device": "br-lan",
        "proto": "static",
        "device": "br-lan",
        "updated": [
                "addresses"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "192.168.1.1",
                        "mask": 24
                }
        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [
                {
                        "address": "fd18:78b1:671d::",
                        "mask": 64,
                        "local-address": {
                                "address": "fd18:78b1:671d::1",
                                "mask": 64
                        }
                }
        ],
        "route": [

        ],
        "dns-server": [

        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {

        }
}
7

I cannot find your router model in the OpenWRT ToH and your output shows a total different model (I actually have a Dynalink DL-WRX36 which has that board).
Are you running genuine OpenWRT?
Your interface also does not look very familiar

8

My bad, we need ifstatus wan6 output.

9 
{
        "up": false,
        "pending": true,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "proto": "dhcpv6",
        "device": "wan",
        "data": {

        }
}
10

What are the other options for "Working Mode" on the upstream device?
If you connect your PC to the upstream device instead of OpenWrt router will it get 2xxx: IPv6 address?

11

OP has two devices, not only the WRX36.
and the ubus call system board looks legit to me ?

1 Like
12

The other Working Modes are:
image

However, they do not work. It is only DHCPv6 for some reason.

And yes I mentioned earlier that the upstream device gives me IPv6 connection when connecting it directly to a PC.

13

Yes, I have two devices. The Upstream Device is the Model O3 by Suncomm. And the device behind the is the Dynalink Router.

1 Like
14

An LTE ISP should give you a single public (GUA) /64 subnet. This can then be relayed through your network so that each of your devices have unique IPs within the same /64.

When you connect the modem directly to a laptop, check the laptop's network status and confirm that it has a GUA /64. Also it should have a DNS server reachable via v6, this is often the link local IP of the next upstream router (i.e. the modem).

15

This is the case when I connect the router directly to a computer.

However, in my case with another router in row the IPv6 test fails. Without NAT6 and SLAAC, the IPv6 does not even go through to the other router. I need both enabled to get an IP on the Dynalink router behind. No matter what I do the IP test fails...