/srv/irclogs.ubuntu.com/2021/12/19/#ubuntu-server.txt

=== genii is now known as genii-core
Devil_KinJanC: went through the feature list, and yeah couldn't directly spot any in the 2.1 release. ZFS 2.0 was a different beast 09:25
jafa2hi guys, netplan dhcp6:yes doesn't seem to result in getting a ipv6 address from the isp... manually running dhclient -6 gets an ip13:55
jafa2the interfaces does get an ipv6 link local as expected13:56
jafa2is there something I need to configure in netplan or dhclient so the system picks up the ipv6 address automatically?13:59
tomreyndid you read the description of the dhcp6 option at https://netplan.io/reference/#common-properties-for-all-device-types ?14:21
tomreyni'm not sure that any of this is causing it, but dhcp6 is definitely more complex than just dhcp4, due to more options.14:21
tomreynwhich netplan renderer you're using can also matter (and you haven't told us)14:22
tomreynjafa2: ^14:22
jafa2hi tomreyn, not seeing anything interesting in the dhcp overrides documentation. Not specifying the renderer (ubuntu server 20.04) and I haven't figured out how to get netplan to tell me14:40
jafa2can I read back from netplan which renderer it is using?14:41
tomreyni'm not aware of where this is stated, if anywhere, but i believe the default renderer is systemd-networkd14:42
tomreyni wasn't thinking of dhcp overrides, just of statements such as "Autoconfiguration will still honour the contents of the router advertisement14:43
tomreynand only use DHCP if requested in the RA."14:43
tomreynif you look in /run/ you should see either a systemd-networkd or netplan configuration for this interface, i think14:44
jafa2seeing things under /run/systemd/network/14:48
jafa210-netplan-wan.network shows DHCP=yes LinkLocalAddressing=ipv6 and some not-interesitng DHCP options14:50
jafa2i can put dhclient -6 in rc.local but it seems like something netplan should be handling14:55
fricklerjafa2: check with tcpdump whether you are getting RAs from your isp. if not, dhcp6 will not be of much use to you anyway, as you will only have an address, but no router15:54
jafa2tcpdump.... checking17:32
jafa2after doing a dhclient -6 I get a /128 address (the 'every sperm is precious' school of ipv6 addressing) and the server has ipv6 internet access17:33
jafa2getting "ip6-allnodes: ICMP6, router advertisement, length 32"17:35
jafa2the RA contains a cisco link layer address - seems pretty normal17:38
jafa2oh, hang on...17:40
jafa2working!17:47
jafa2the DHCP advertise was being blocked by ip6tables...17:48
jafa2guess conntrack isn't tracking it17:48
jafa2reboot - everything came up nicely17:50
jafa2because the ISP is only handling out a single ipv6 /128 address I created an ip6tables postrouting masquerade rule and a forward contrack rule so other devices on the lan can route through this server. However when a device attempts to send ipv6 the server sends back an ICMP Destination Unreachable (Beyond the scope of source address) error18:01
jafa2playing around with trying to request a /6418:31
kenyonjafa2: you use DHCPv6 Prefix Delegation to get a routed subnet. the /128 is normal and typical for the WAN link.21:04
kenyonjafa2: see also #IPv6 here on Libera.Chat21:04
=== mmebsd is now known as linsux
jafa2kenyon - thanks23:07

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