Recently my Ubuntu install (22.04) has been creating around 5-6 bridge networks, these seem to prevent internet access. I can manually go through and take down each interface and delete the bridge via "brctl delbr", but it's a pain to go through this each time. Even on restart these bridges are re-created.
This is the output of route when the bridges (all the br-* interfaces) are active and preventing internet access:
➜ ~ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.0.1 0.0.0.0 UG 600 0 0 wlp0s20f3
link-local 0.0.0.0 255.255.0.0 U 1000 0 0 wlp0s20f3
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
172.18.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-d426659a2acb
172.19.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-fc0b0e819621
172.20.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-28a1cb513e25
172.21.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-a453127c4011
172.23.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-d80fc876a9ed
192.168.0.0 0.0.0.0 255.255.255.0 U 600 0 0 wlp0s20f3
192.168.0.0 0.0.0.0 255.255.240.0 U 0 0 0 br-238ff410ee26
Here's the output of syslog for one of the bridge interfaces:
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.1071] manager: (br-d80fc876a9ed): new Bridge device (/org/freedesktop/NetworkManager/Devices/9)
Nov 8 18:25:06 willis-laptop avahi-daemon[1530]: Joining mDNS multicast group on interface br-d80fc876a9ed.IPv4 with address 172.23.0.1.
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2016] device (br-d80fc876a9ed): state change: unmanaged -> unavailable (reason 'connection-assumed', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2026] device (br-d80fc876a9ed): state change: unavailable -> disconnected (reason 'connection-assumed', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop avahi-daemon[1530]: New relevant interface br-d80fc876a9ed.IPv4 for mDNS.
Nov 8 18:25:06 willis-laptop avahi-daemon[1530]: Registering new address record for 172.23.0.1 on br-d80fc876a9ed.IPv4.
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2042] device (br-d80fc876a9ed): Activation: starting connection 'br-d80fc876a9ed' (12323e12-58ee-427c-9b11-967ff562ba1a)
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2063] device (br-d80fc876a9ed): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2072] device (br-d80fc876a9ed): state change: prepare -> config (reason 'none', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2076] device (br-d80fc876a9ed): state change: config -> ip-config (reason 'none', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2107] device (br-d80fc876a9ed): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2274] device (br-d80fc876a9ed): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2277] device (br-d80fc876a9ed): state change: secondaries -> activated (reason 'none', sys-iface-state: 'external')
Nov 8 18:25:06 willis-laptop NetworkManager[1536]: <info> [1667960706.2284] device (br-d80fc876a9ed): Activation: successful, device activated.
