IPv6 network on Ubuntu Server 22.04

Can't seem to get the IPv6 network to work.

Unfortunately, I decided to reinstall the system anyway. And IPv6 doesn't work for me either.

Given: Dedicated IPv4 like: 45.80.XX.XX/32 and gateway 10.0.0.1;IPv6 subnet: 2a03:XX:XX::5b8/125 (/125 prefix) and gateway 2a03:XX:XX::5b9

Bottom line: IPv4 works fine, but IPv6 doesn’t want to do anything...

Question: Tell me, please, a possible solution to the problem with IPv6.

My config is in /etc/netplan/00-network-all.yaml

network:  version: 2  renderer: networkd  ethernets:    ens3:      dhcp4: no      dhcp6: no      addresses:        - 45.80.XX.XX/32        - 2a03:XX:XX::5b8/125      nameservers:       addresses:        - 1.1.1.1        - 8.8.8.8        - 2606:4700:4700::1111        - 2001:4860:4860::8888      routes:        - to: 0.0.0.0/0 # default          via: 10.0.0.1 # Gateway IPv4          metric: 100          on-link: true        - to: ::/0 # default          via: 2a03:XX:XX::5b9 # Gateaway IPv6          metric: 200          on-link: true

ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever    inet6 ::1/128 scope host       valid_lft forever preferred_lft forever2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:XX:XX:XX brd ff:ff:ff:ff:ff:ff    altname enp0s3    inet 45.80.XX.XX/32 scope global ens3       valid_lft forever preferred_lft forever    inet6 2a03:XX:XX::5b8/125 scope global       valid_lft forever preferred_lft forever    inet6 fe80::XX:XX:XX:1904/64 scope link       valid_lft forever preferred_lft forever

ip -6 r

ip -6 rCode:::1 dev lo proto kernel metric 256 pref medium2a03:XX:XX::5b8/125 dev ens3 proto kernel metric 256 pref mediumfe80::/64 dev ens3 proto kernel metric 256 pref mediumdefault via 2a03:XX:XX::5b9 dev ens3 proto static metric 200 onlink pref medium

ip neigh

10.0.0.1 dev ens3 lladdr 02:00:00:00:00:01 REACHABLE2a03:XX:XX::5b9 dev ens3  FAILED

route -6

Kernel IPv6 routing tableDestination                    Next Hop                   Flag Met Ref Use Ifip6-localhost/128              [::]                       U    256 2     0 lomyhost/125                     [::]                       U    256 1     0 ens3fe80::/64                      [::]                       U    256 1     0 ens3[::]/0                         _gateway                   UGH  200 1     0 ens3ip6-localhost/128              [::]                       Un   0   5     0 lomyhost/128                     [::]                       Un   0   2     0 ens3myhost/128                     [::]                       Un   0   2     0 ens3ip6-mcastprefix/8              [::]                       U    256 4     0 ens3[::]/0                         [::]                       !n   -1  1     0 lo

P.S. In IPv6 routing table there is a strange "UGH" flag, maybe it should be just "UG" ???