Score:1

Ubuntu

IPv6 network on Ubuntu Server 22.04

Nick

11/20/23, 6:11 PM

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 forever


2: 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 r
Code:
::1 dev lo proto kernel metric 256 pref medium
2a03:XX:XX::5b8/125 dev ens3 proto kernel metric 256 pref medium
fe80::/64 dev ens3 proto kernel metric 256 pref medium
default 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 REACHABLE
2a03:XX:XX::5b9 dev ens3  FAILED

route -6

Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
ip6-localhost/128              [::]                       U    256 2     0 lo
myhost/125                     [::]                       U    256 1     0 ens3
fe80::/64                      [::]                       U    256 1     0 ens3
[::]/0                         _gateway                   UGH  200 1     0 ens3
ip6-localhost/128              [::]                       Un   0   5     0 lo
myhost/128                     [::]                       Un   0   2     0 ens3
myhost/128                     [::]                       Un   0   2     0 ens3
ip6-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" ???

2588

1 + 0

server

ipv6

networking

netplan

Score:0

Ubuntu

slangasek

11/21/23, 8:38 PM

You have a misconfiguration here, in that you are declaring two host addresses on the interface and one of them is the network address. Your ipv6 config should be:

addresses:
  - 2a03:XX:XX::5ba/125
routes:
  - to: ::/0 # default
    via: 2a03:XX:XX::5b9

+ 5

Nick

11/22/23, 11:17 AM

Yes, I experimented and forgot to restore the previous configuration. But, the situation has not changed in any way IPv6 still does not work ...

Nick

11/22/23, 11:21 AM

I think the problem is that the Link-Local address has disappeared. But, **how to restore it ???**

slangasek

11/24/23, 3:29 AM

can you post the ip -6 r and ip neigh output from the affected system after correcting the netplan config and running `netplan apply`? I don't see anything in the netplan config that would break link-local addresses, so this may be configured elsewhere on the system and conflicting with the expected behavior.

Nick

11/24/23, 7:31 AM

Unfortunately, I reinstalled the system and updated the header. P.S. I am usually use `sudo netplan try`... P.P.S. **Very need help with IPv6!**

slangasek

12/7/23, 1:45 AM

so, I see your update to the contents of the question and it still shows you using 5b*8*, which is the network address, as the host address; instead of 5b*a*. and you should avoid using `on-link: true` here which is unnecessary and is potentially obfuscating things in the output.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: IPv6 network on Ubuntu Server 22.04

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.