Public bug reported: My network has both DHCPv6 and SLAAC for IPv6. From both a privacy perspective and readability reasons, DHCPv6 should *always* be preferred over SLAAC addresses when available.
NetworkManager has always been able to adhere to that by simply setting ip6.privacy=0 for the connection. So if you would - for instance - run `curl ifconfig.co`, the DHCPv6 address would be used to connect to the outside world. Since the update to 1.36.6, this is no longer the case. NetworkManager now routes outgoing traffic through the SLAAC address, even if ip6.privacy=0 is set for the connection. Setting net.ipv6.conf.all.use_tempaddr = 0 and net.ipv6.conf.<interface>.use_tempaddr = 0 with sysctl also no longer has any effect. Physically removing the SLAAC addresses or disabling RA's altogether is the only way to stop NetworkManager from prefering SLAAC over DHCPv6 now. Looking at the changelog of NetworkManager 1.36.6, things regarding IP address order and temporary addresses have been changed in that release: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/blob/nm-1-36/NEWS Unfortunately, this introduced this bug, which is really breaking a lot of my use cases. I should note that the bug is not present in NetworkManager 1.38.0 on Debian sid. That just prefers DHCPv6 addresses when available, like it should. ** Affects: network-manager (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1977619 Title: DHCPv6 addresses are no longer preferred over SLAAC addresses Status in network-manager package in Ubuntu: New Bug description: My network has both DHCPv6 and SLAAC for IPv6. From both a privacy perspective and readability reasons, DHCPv6 should *always* be preferred over SLAAC addresses when available. NetworkManager has always been able to adhere to that by simply setting ip6.privacy=0 for the connection. So if you would - for instance - run `curl ifconfig.co`, the DHCPv6 address would be used to connect to the outside world. Since the update to 1.36.6, this is no longer the case. NetworkManager now routes outgoing traffic through the SLAAC address, even if ip6.privacy=0 is set for the connection. Setting net.ipv6.conf.all.use_tempaddr = 0 and net.ipv6.conf.<interface>.use_tempaddr = 0 with sysctl also no longer has any effect. Physically removing the SLAAC addresses or disabling RA's altogether is the only way to stop NetworkManager from prefering SLAAC over DHCPv6 now. Looking at the changelog of NetworkManager 1.36.6, things regarding IP address order and temporary addresses have been changed in that release: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/blob/nm-1-36/NEWS Unfortunately, this introduced this bug, which is really breaking a lot of my use cases. I should note that the bug is not present in NetworkManager 1.38.0 on Debian sid. That just prefers DHCPv6 addresses when available, like it should. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1977619/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
