ddns-scripts: Fails to determine public IPv6 address since update to OpenWrt 25.12

Package Name

ddns-scripts

Maintainer

(@feckert)

OpenWrt Version

25.12.1

OpenWrt Target/Subtarget

mvebu/cortexa9

Steps to Reproduce

1. Upgraded to OpenWrt 25.12.1 from 24.10.6
2. Observed that DDNS updates (using the "nsupdate" method) no longer work.

Actual Behaviour

The public IPv6 address is no longer determined correctly:

115038       : Detecting current IP using source: interface
 115038       : #> ip -o -br -js addr show dev 'wan' scope global | /usr/bin/jsonfilter -e '@[0].addr_info[0].local'
 115038       : Current IP 'fd94:2ff5:9671:12::1' detected on interface 'wan'
 115038       : Detected IP: fd94:2ff5:9671:12::1
 115038       : Update needed - L: 'fd94:2ff5:9671:0012:0000:0000:0000:0001' <> R: '2a00:xxxx:xxxx:0e12:0000:0000:0000:0001'
 115039 ERROR : No or private or invalid IP 'fd94:2ff5:9671:0012:0000:0000:0000:0001' given! Please check your configuration

Excerpt from /etc/config/network:

config device
        option name 'wan'
        option macaddr '12:34:56:10:b9:4f'

config interface 'wan'
        option device 'wan'
        option proto 'dhcp'
        option metric '10'

config interface 'wan6'
        option device 'wan'
        option proto 'dhcpv6'
        option reqaddress 'try'
        option reqprefix 'auto'
        option ip6assign '64'
        option metric '10'
        option sourcefilter '0'

Excerpt from ip a:

7: wan@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 12:34:56:10:b9:4f brd ff:ff:ff:ff:ff:ff permaddr 12:34:56:10:b9:4f
    inet 100.112.143.195/16 brd 100.112.255.255 scope global wan
       valid_lft forever preferred_lft forever
    inet6 fd94:2ff5:9671:12::1/64 scope global noprefixroute
       valid_lft forever preferred_lft forever
    inet6 2a00:xxxx:xxxx:e12::1/64 scope global dynamic noprefixroute
       valid_lft 2933sec preferred_lft 2933sec
    inet6 2a00:xxxx:yyyy:47::131e/128 scope global dynamic noprefixroute
       valid_lft 2932sec preferred_lft 2932sec
    inet6 fe80::6034:56ff:fe10:b94f/64 scope link proto kernel_ll
       valid_lft forever preferred_lft forever

Confirmation Checklist

• The package is maintained in this repository.
• I understand that issues related to the base OpenWrt repository or LuCI repository will be closed.
• I am reporting an issue for OpenWrt, not an unsupported fork.

Start with the ddns-scripts IPv6 address detection path and reproduce the logged interface command against the supplied network configuration and addresses. Done means the public global IPv6 address is selected instead of the private fd94 address and the nsupdate DDNS update succeeds.