Ddns ipv6 and interface naming

Installing and Using OpenWrt Network and Wireless Configuration
1

Now that my ISP also offers IPv6 I have added an entry in ddns for it. I had a couple of problems, now it works but I would like to clean it up if possible.

  1. the GUI does not allow me to leave username empty, even if the field for duckdns with tokens is not needed. Is it normal?

  2. I must add "ip_interface pppoe-wan".... other options detect a local address or throw an error for "eth1". I thought "wan" / "wan6" would work as generic placeholders.

This is the service definition from /etc/config/ddns:

config service 'duckdns_v6'
        option domain 'redacted.duckdns.org'
        option enabled '1'
        option ip_interface 'pppoe-wan'
        option ip_source 'interface'
        option lookup_host 'redacted.duckdns.org'
        option password 'redacted'
        option retry_count '10'
        option service_name 'duckdns.org'
        option use_https '1'
        option use_ipv6 '1'
        option retry_max_count '10'
        option use_syslog '2'
2

Yes. See https://openwrt.org/docs/guide-user/services/ddns/client#duckdnsorg

No, these are real interface names.

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3

Thanks for the first one, I added a dummy value to keep it happy.

For the second one: if I understand correctly, "wan6" would be an acceptable option if my upstream IPv6 came from DHCPv6. Since it comes via ppp, I need to be explicit here. Right?

4

Not exactly. The difference is real interface vs. virtual or dynamic.
You will see your interfaces like wan/wan6/etc. even if you unplug the ethernet cable, however ppp* will (temporarily) appear when the connection is established.

Cannot check this myself, so I'm curious whether you have your IPv6 shown in
ip -o addr show | grep inet6

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5

yes, it is shown besides pppoe-wan.

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6

Just to clarify, is this because you want to access a service on your router remotely? :slight_smile: If it's because you want to reach a service on a device behind your router, you need the DNS record to point to the GUA used on that device, not the router since we generally avoid NAT with IPv6.

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7

yup, openvpn running on the router itself.
I also have to install the update script on the raspi I use for ADSB, precisely for that reason (with the static tunnel address that was not an issue)

8

Ok. That makes sense. :slight_smile:

A lot of people have a very NAT centered thinking so I always feel the need to make sure people set up what they actually need, not what they mistakenly think they need. :slight_smile:

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