No IPV6 connection for clients

Installing and Using OpenWrt Network and Wireless Configuration
1

Hi,

WRT32X running a recent davidx502 build.

I have IPV6 connectivity to my WRT32X, IPV6 Upstream/WAN6 shows connected and I can successfully run "ping6 google.com" from SSH.

However, connected clients over wifi or ethernet have no IPV6 connection. I also see the following message repeated inside the system log:

Fri Oct 12 16:07:11 2018 daemon.warn odhcpd[2475]: A default route is present but there is no public prefix on br-lan thus we don't announce a default route!

Not totally sure where to start debugging this, so looking to use it as a learning opportunity even if it's not a big deal right now!

Thanks

2

How big of a prefix can you get from your ISP? If they give you a /64 it might be assigned to the WAN and then there is nothing left for the LAN. You can try requesting a /60 or /56 there's some way to adjust that in LUCI I think in the wan setting.

3 
uci show network
ubus call network.interface.wan6 status
4

Thanks, it is /64 i think. I can see that setting int the WAN6 options, changing to /56 doesn't seem to have made a difference. I've reverted it back to 'automatic'.

5 
# uci show network
network.loopback=interface
network.loopback.ifname='lo'
network.loopback.proto='static'
network.loopback.ipaddr='127.0.0.1'
network.loopback.netmask='255.0.0.0'
network.globals=globals
network.globals.ula_prefix='fdb2:3369:847e::/48'
network.lan=interface
network.lan.type='bridge'
network.lan.ifname='eth0.1'
network.lan.proto='static'
network.lan.ipaddr='192.168.1.1'
network.lan.netmask='255.255.255.0'
network.lan.ip6assign='60'
network.wan=interface
network.wan.ifname='eth1.2'
network.wan.proto='dhcp'
network.wan6=interface
network.wan6.ifname='eth1.2'
network.wan6.proto='dhcpv6'
network.wan6.reqaddress='try'
network.wan6.reqprefix='auto'
network.@switch[0]=switch
network.@switch[0].name='switch0'
network.@switch[0].reset='1'
network.@switch[0].enable_vlan='1'
network.@switch_vlan[0]=switch_vlan
network.@switch_vlan[0].device='switch0'
network.@switch_vlan[0].vlan='1'
network.@switch_vlan[0].ports='0 1 2 3 5t'
network.@switch_vlan[1]=switch_vlan
network.@switch_vlan[1].device='switch0'
network.@switch_vlan[1].vlan='2'
network.@switch_vlan[1].ports='4 6t'
network.vpnserver=interface
network.vpnserver.proto='none'
network.vpnserver.ifname='ovpns0'
network.vpnserver.auto='1'

# ubus call network.interface.wan6 status
{
    "up": true,
    "pending": false,
    "available": true,
    "autostart": true,
    "dynamic": false,
    "uptime": 90,
    "l3_device": "eth1.2",
    "proto": "dhcpv6",
    "device": "eth1.2",
    "updated": [
        "addresses",
        "routes",
        "data"
    ],
    "metric": 0,
    "dns_metric": 0,
    "delegation": true,
    "ipv4-address": [

    ],
    "ipv6-address": [
        {
            "address": "redacted",
            "mask": 64,
            "preferred": 2617,
            "valid": 2617
        },
        {
            "address": "redacted",
            "mask": 64
        }
    ],
    "ipv6-prefix": [

    ],
    "ipv6-prefix-assignment": [

    ],
    "route": [
        {
            "target": "redacated:",
            "mask": 64,
            "nexthop": "::",
            "metric": 256,
            "valid": 2617,
            "source": "::\/0"
        },
        {
            "target": "redacted",
            "mask": 64,
            "nexthop": "::",
            "metric": 256,
            "source": "::\/0"
        },
        {
            "target": "::",
            "mask": 0,
            "nexthop": "redacted",
            "metric": 512,
            "valid": 1707,
            "source": "redacted"
        },
        {
            "target": "::",
            "mask": 0,
            "nexthop": "redacted",
            "metric": 512,
            "valid": 1707,
            "source": "redacted"
        }
    ],
    "dns-server": [
        "redacted"
    ],
    "dns-search": [

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

        ],
        "ipv6-address": [

        ],
        "route": [

        ],
        "dns-server": [

        ],
        "dns-search": [

        ]
    },
    "data": {
        "passthru": "0010002b00000de90025322e30372e323335362e527c3030337c45523131357c423232303138364130303734383200000f001f001d32346137646363376563643040736b7964736c7c33626133313164320000170010fdcfc0a86de5000026a7dcfffec7ecd0"
    }
}
6

I have a very similar DHCPv6-lease on my OpenWrt+Linode.
ipv6-prefix and ipv6-prefix-assignment are also empty.
My prefix is static and it's routed via WAN-address.

7

Where is the delegated prefix, ipv6-prefix is empty? With IPv6 all devices needs global addresses since NAT isn't used which is the reason it isn't enough with IPv6 addresses on the WAN interface.

8

So would this point to a misconfiguration in openwrt or a problem with the ISP modem not providing the prefix?

9

It should be possible to verify with tcpdump:

tcpdump -vvvni any ip6 and udp port 546 &
killall -SIGUSR1 odhcp6c
odhcp6c eth1.2
...
killall tcpdump
10

Thanks, looks like the modem's the problem, then...if I am interpreting this correcting:

...
00:50:14.355581 IP6 (hlim 255, next-header UDP (17) payload length: 154) ... [udp sum ok] dhcp6 advertise (xid=5fe5c7 (client-ID hwaddr type 1 6038e0ce5340) (server-ID hwaddr type 1 24a7dcc7ecd1) (status-code NoPrefixAvail) (status-code NoAddrsAvail) (vendor-class) (user-class)...
...