Hello debian-user, I have an internet connection via a router provided by my ISP. I have a Linux box (Debian Buster) between this router and my internal network in order to provide nicer firewalling and some services like OpenVPN, wifi for guests without access to the internal network, and so on.
In order to provide IPv6 to my internal network, I use IPv6 prefix delegation to get a prefix from the ISP-provided router. That works and my systemd-networkd (systemd version 244.3-1 from backports) config files look somewhat like this: #/etc/systemd/network/10-enp3s0.network <- the "external" interface [Match] Name=enp3s0 [Network] Address=<some RFC1918 IPv4 address> Gateway=<IPv4 gateway> Address=fdxx:xxxx:xxxx:xxxx::1/64 IPv6AcceptRA=yes DHCP=ipv6 IPv6PrivacyExtensions=true [DHCPv6] ForceDHCPv6PDOtherInformation=yes #/etc/systemd/network/20-br0.network <- the "internal" interface [Match] Name=br0 [Network] Address=<some RFC1918 IPv4 address> Address=fdxx:xxxx:xxxx:yyyy::1/64 IPv6PrefixDelegation=yes [IPv6PrefixDelegation] Managed=yes OtherInformation=yes RouterLifetimeSec=7200 EmitDNS=yes DNS=fdxx:xxxx:xxxx:yyyy::1 DNSLifetimeSec=7200 [IPv6Prefix] Prefix=fdxx:xxxx:xxxx:yyyy::/64 ValidLifetimeSec=7200 PreferredLifetimeSec=3600 That works quite nicely and I get both ULA addresses and some dynamic prefix from my ISP for the internal net. Unfortunately, whenever the public IPv6 prefix changes [enforced nightly by the ISP :-( ] the prefix delegation is lost and I only retain IPv4 and the ULA addresses on my internal network. The external interface enp3s0 gets a new public IPv6 address without trouble, though. Debug logs from systemd-networkd contain the following at the relevant time (nothing else relevant, though): DHCPv6 CLIENT: Sent RENEW DHCPv6 CLIENT: Next retransmission in 9s DHCPv6 CLIENT: REPLY Status Binding unavailable It seems that the built-in DHCPv6 client of systemd tries to renew the old prefix and is denied. It does not seem to request a new prefix. Does anybody have some experience with this? Is this a bug in systemd-networkd or the ISP-provided router? Some other problem? It is also a bit annoying to implement a workaround. While "networkctl reconfigure enp3s0" does the trick and gets a new delegated prefix, I am not sure how to automate this command. There seems to be no tool to show the delegated prefixes, so I cannot find out when they are lost. Does somebody have an idea? Any help appreciated. Tobias
