Seb: This is a bug in the Ubuntu-only ofono patches where the interface name is being generated incorrectly.
"hfp/org/bluez/hci0/dev_2C_8A_72_15_A8_55" is not a valid interface name under "/proc/sys/net/ipv6/conf/" $ ls /proc/sys/net/ipv6/conf/ all default enp0s29f7u5i6 enp2s0 lo lxcbr0 tun0 virbr0 virbr0-nic vlan99 wlp3s0 As I said in the initial report this is for a (currently disabled) remote bluetooth device providing (I presume) a PAN connection. I think this is being attempted since in the dim-distant past I connected the PC over Bluetooth to the smartphone: $ nmcli con show "HTC One M8 Network" connection.id: HTC One M8 Network connection.uuid: 01aea27a-7318-4d2f-b9ab-311654d836b9 connection.interface-name: -- connection.type: bluetooth connection.autoconnect: no connection.autoconnect-priority: 0 connection.timestamp: 0 connection.read-only: no connection.permissions: connection.zone: -- connection.master: -- connection.slave-type: -- connection.autoconnect-slaves: -1 (default) connection.secondaries: connection.gateway-ping-timeout: 0 connection.metered: unknown connection.lldp: -1 (default) ipv4.method: auto ipv4.dns: ipv4.dns-search: ipv4.dns-options: (default) ipv4.dns-priority: 0 ipv4.addresses: ipv4.gateway: -- ipv4.routes: ipv4.route-metric: -1 ipv4.ignore-auto-routes: no ipv4.ignore-auto-dns: no ipv4.dhcp-client-id: -- ipv4.dhcp-timeout: 0 ipv4.dhcp-send-hostname: yes ipv4.dhcp-hostname: -- ipv4.dhcp-fqdn: -- ipv4.never-default: no ipv4.may-fail: no ipv4.dad-timeout: -1 (default) ipv6.method: auto ipv6.dns: ipv6.dns-search: ipv6.dns-options: (default) ipv6.dns-priority: 0 ipv6.addresses: ipv6.gateway: -- ipv6.routes: ipv6.route-metric: -1 ipv6.ignore-auto-routes: no ipv6.ignore-auto-dns: no ipv6.never-default: no ipv6.may-fail: yes ipv6.ip6-privacy: -1 (unknown) ipv6.addr-gen-mode: stable-privacy ipv6.dhcp-send-hostname: yes ipv6.dhcp-hostname: -- bluetooth.bdaddr: 2C:8A:72:15:A8:55 bluetooth.type: panu ** Summary changed: - IPv6 property path is too long + Bluetooth/Cellular PAN: IPv6 property path is too long -- 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/1744076 Title: Bluetooth/Cellular PAN: IPv6 property path is too long Status in network-manager package in Ubuntu: New Bug description: On 16.04 there are lots of warnings for paths generated under /proc/sys/net/ipv6/conf/ of the form: NetworkManager[2043]: <error> [1516281647.5546] Failed asserting path component: "hfp/org/bluez/hci0/dev_2C_8A_72_15_A8_55" NetworkManager[2043]: <warn> [1516281647.5546] IPv6 property path is too long: '/proc/sys/net/ipv6/conf/hfp/org/bluez/hci0/dev_2C_8A_72_15_A8_55/accept_ra' These 2 messages occur for all of: accept_ra accept_ra_defrtr accept_ra_pinfo accept_ra_rtr_pref disable_ipv6 hop_limit use_tempaddr In this case the device is a (currently disconnected) cellular phone: bluez: BT device HTC One M8 (2C:8A:72:15:A8:55) added (DUN NAP) --- ApportVersion: 2.20.1-0ubuntu2.15 Architecture: amd64 CurrentDesktop: LXDE DistroRelease: Ubuntu 16.04 EcryptfsInUse: Yes IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) # Include files from /etc/network/interfaces.d: source-directory /etc/network/interfaces.d NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=false WimaxEnabled=true Package: network-manager 1.2.6-0ubuntu0.16.04.2 PackageArchitecture: amd64 ProcVersionSignature: Ubuntu 4.13.0-25.29~16.04.2-lowlatency 4.13.13 Tags: third-party-packages xenial Uname: Linux 4.13.0-25-lowlatency x86_64 UpgradeStatus: Upgraded to xenial on 2017-09-17 (122 days ago) UserGroups: adm audio cdrom dialout disk floppy libvirtd lp lpadmin lxd plugdev root sudo users video wireshark _MarkForUpload: True mtime.conffile..etc.dbus-1.system.d.nm-dispatcher.conf: 2015-11-04T09:44:08.042438 mtime.conffile..etc.dbus-1.system.d.nm-ofono.conf: 2015-11-04T09:44:08.042438 nmcli-nm: RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN running 1.2.6 connected started full enabled enabled enabled enabled disabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1744076/+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