Ula prefixed addresss - make it stop

My Turris Omnia (5.2.7) seems to have decided to start assigning ula prexfied IPv6 addresses to my LAN again and this time I can’t figure out how to stop it. I need to do this because my SIP phone is not very smart and will not connect to the gateway with a ULA prefixed address. Previously I have added ip6class wan6 to the lan config, so that it only assigns global addresses from my ISP, as well as comment out the global ula prefix. Some combination of these has worked until now and still does intermittently but most of the time, the ula prefixes are back. How do I turn this off for good?

A snippet from my /etc/config/network is as follows:

config globals 'globals'
#	option ula_prefix 'fd0c:9165:f680::/48'

config interface 'lan'
option type 'bridge'
option proto 'static'
option ipaddr '192.168.1.1'
option netmask '255.255.255.0'
option ip6assign '60'
option bridge_empty '1'
list ip6class wan6
list ifname 'lan0'
list ifname 'lan1'
list ifname 'lan2'
list ifname 'lan3'
list ifname 'lan4'

Hello @mnd999,
go to the LuCI → Network settings → Global network options and set IPv6 ULA-Prefix to empty value. Apply the settings and restart the networking.

As an alternative, you can do it from cli by running uci delete network.globals.ula_prefix && uci commit && service network restart and verifying you do not have any ULA prefix configured on LAN interface.

No, that doesn’t do it - I’m still getting fd14: prefixed addresses everywhere as well as 2001: which is the correct prefix.

Can you please paste here the output of ip -6 addr show

Sure - on the router:

root@turris:~# ip -6 addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 state UNKNOWN qlen 1000
inet6 ::1/128 scope host
   valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 532
inet6 fe80::da58:d7ff:fe00:59b1/64 scope link
   valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 532
inet6 fe80::da58:d7ff:fe00:59af/64 scope link
   valid_lft forever preferred_lft forever
4: eth2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 532
inet6 fe80::da58:d7ff:fe00:59b0/64 scope link
   valid_lft forever preferred_lft forever
17: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
inet6 2001:8b0:da3:76a2::1/64 scope global dynamic noprefixroute
   valid_lft 6398sec preferred_lft 6398sec
inet6 fe80::6f0:21ff:fe23:18df/64 scope link
   valid_lft forever preferred_lft forever
23: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
inet6 fe80::6f0:21ff:fe24:8fc/64 scope link
   valid_lft forever preferred_lft forever
24: wlan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
inet6 fe80::6f0:21ff:fe23:18df/64 scope link
   valid_lft forever preferred_lft forever
26: vethDEAYHM@if25: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
inet6 fe80::fc22:84ff:fe3e:71b8/64 scope link
   valid_lft forever preferred_lft forever
28: vethIYSY4Q@if27: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
inet6 fe80::fcce:f5ff:fec0:c551/64 scope link
   valid_lft forever preferred_lft forever
30: pppoe-wan: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1492 state UNKNOWN qlen 3
inet6 2001:8b0:1111:1111:0:ffff:51bb:a572/128 scope global dynamic noprefixroute
   valid_lft 6398sec preferred_lft 2798sec
inet6 fe80::5429:9be3:a0dd:524a/10 scope link
   valid_lft forever preferred_lft forever

On (a) client:

2: enp0s31f6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP qlen 1000
inet6 2001:8b0:da3:76a2:d5dd:df48:83b1:a8fc/64 scope global dynamic mngtmpaddr noprefixroute
   valid_lft 6256sec preferred_lft 6256sec
inet6 fd14:efe2:f14a:1:cf79:1451:489:6295/64 scope global deprecated dynamic mngtmpaddr noprefixroute
   valid_lft 1050sec preferred_lft 0sec
inet6 2001:8b0:da3:76a2:4630:5b97:83a2:3e21/64 scope global dynamic noprefixroute
   valid_lft 6448sec preferred_lft 6448sec
inet6 fd14:efe2:f14a:1:4100:a81e:abce:9b2/64 scope global deprecated dynamic noprefixroute
   valid_lft 1051sec preferred_lft 0sec
inet6 fe80::6f02:958c:40c2:b263/64 scope link noprefixroute

Is it the same situation when you reboot the client?

No, that does seem to have fixed it for now. I’ll keep an eye on it.

Thanks a lot for the help.