What are these unexpected network devices which appear in kernel log?

Question

I have enp7s0 (ethernet) and wlp5s0 (wifi) that I've been using, but there's some other network interfaces that I don't recognise that keep showing periodically in dmesg. What are they, and how can I remove them?

$ sudo dmesg -w
[ 5400.052789] device veth517d19f entered promiscuous mode
[ 5400.052861] br-b6747aa2af8f: port 1(veth517d19f) entered blocking state
[ 5400.052862] br-b6747aa2af8f: port 1(veth517d19f) entered forwarding state
[ 5400.213261] eth0: renamed from veth244244e
[ 5400.222378] IPv6: ADDRCONF(NETDEV_CHANGE): veth517d19f: link becomes ready
[ 5568.791784] veth244244e: renamed from eth0
[ 5568.810950] br-b6747aa2af8f: port 1(veth517d19f) entered disabled state
[ 5568.830903] br-b6747aa2af8f: port 1(veth517d19f) entered disabled state
[ 5568.831278] device veth517d19f left promiscuous mode
[ 5568.831280] br-b6747aa2af8f: port 1(veth517d19f) entered disabled state
[ 5568.880757] br-b6747aa2af8f: port 1(veth011f3f5) entered blocking state
[ 5568.880760] br-b6747aa2af8f: port 1(veth011f3f5) entered disabled state
[ 5568.880814] device veth011f3f5 entered promiscuous mode
[ 5568.880962] br-b6747aa2af8f: port 1(veth011f3f5) entered blocking state
[ 5568.880964] br-b6747aa2af8f: port 1(veth011f3f5) entered forwarding state
[ 5569.077840] eth0: renamed from veth6e8382e
[ 5569.093718] IPv6: ADDRCONF(NETDEV_CHANGE): veth011f3f5: link becomes ready
[ 5737.805813] veth6e8382e: renamed from eth0
[ 5737.823318] br-b6747aa2af8f: port 1(veth011f3f5) entered disabled state
[ 5737.843811] br-b6747aa2af8f: port 1(veth011f3f5) entered disabled state
[ 5737.844340] device veth011f3f5 left promiscuous mode
[ 5737.844344] br-b6747aa2af8f: port 1(veth011f3f5) entered disabled state
[ 5737.893657] br-b6747aa2af8f: port 1(vethd8bfbd6) entered blocking state
[ 5737.893661] br-b6747aa2af8f: port 1(vethd8bfbd6) entered disabled state
[ 5737.893736] device vethd8bfbd6 entered promiscuous mode
[ 5737.893886] br-b6747aa2af8f: port 1(vethd8bfbd6) entered blocking state
[ 5737.893890] br-b6747aa2af8f: port 1(vethd8bfbd6) entered forwarding state
[ 5738.172548] eth0: renamed from veth7906981
[ 5738.188736] IPv6: ADDRCONF(NETDEV_CHANGE): vethd8bfbd6: link becomes ready
[ 5906.354088] veth7906981: renamed from eth0
[ 5906.369700] br-b6747aa2af8f: port 1(vethd8bfbd6) entered disabled state
[ 5906.389362] br-b6747aa2af8f: port 1(vethd8bfbd6) entered disabled state
[ 5906.389734] device vethd8bfbd6 left promiscuous mode
[ 5906.389737] br-b6747aa2af8f: port 1(vethd8bfbd6) entered disabled state
[ 5906.443306] br-b6747aa2af8f: port 1(veth7a88bf4) entered blocking state
[ 5906.443309] br-b6747aa2af8f: port 1(veth7a88bf4) entered disabled state
[ 5906.443354] device veth7a88bf4 entered promiscuous mode
[ 5906.443425] br-b6747aa2af8f: port 1(veth7a88bf4) entered blocking state
[ 5906.443426] br-b6747aa2af8f: port 1(veth7a88bf4) entered forwarding state
[ 5906.637888] eth0: renamed from veth9acd0b3
[ 5906.659074] IPv6: ADDRCONF(NETDEV_CHANGE): veth7a88bf4: link becomes ready
[ 6074.517484] veth9acd0b3: renamed from eth0
[ 6074.529161] br-b6747aa2af8f: port 1(veth7a88bf4) entered disabled state
[ 6074.544507] br-b6747aa2af8f: port 1(veth7a88bf4) entered disabled state
[ 6074.544814] device veth7a88bf4 left promiscuous mode
[ 6074.544815] br-b6747aa2af8f: port 1(veth7a88bf4) entered disabled state
[ 6074.582235] br-b6747aa2af8f: port 1(veth7cc8283) entered blocking state
[ 6074.582238] br-b6747aa2af8f: port 1(veth7cc8283) entered disabled state
[ 6074.582284] device veth7cc8283 entered promiscuous mode
[ 6074.582354] br-b6747aa2af8f: port 1(veth7cc8283) entered blocking state
[ 6074.582355] br-b6747aa2af8f: port 1(veth7cc8283) entered forwarding state
[ 6074.771300] eth0: renamed from veth5a7e47a
[ 6074.791442] IPv6: ADDRCONF(NETDEV_CHANGE): veth7cc8283: link becomes ready

$ ip -br -c addr show
lo               UNKNOWN        127.0.0.1/8 ::1/128
enp7s0           UP             10.10.10.1/8 fe80::a66e:xxxx:e22:xxxx/64
wlp5s0           UP             192.168.18.193/24 fe80::d28c:xxxx:6da5:xxxx/64
virbr0           DOWN           192.168.122.1/24
virbr1           DOWN           192.168.39.1/24
lxcbr0           DOWN           10.0.3.1/24
br-e32feb7cbdc6  DOWN           172.23.0.1/16
br-ef8e425d866f  DOWN           172.21.0.1/16
br-0d1de33a9fd1  DOWN           172.18.0.1/16
br-1535ef132d94  DOWN           172.24.0.1/16
br-3daca6071d2e  DOWN           172.20.0.1/16
docker0          DOWN           172.17.0.1/16
br-80a4ad7261ed  DOWN           172.22.0.1/16
br-b6747aa2af8f  UP             172.19.0.1/16 fe80::42:bff:xxxx:xxxx/64
vethed6ff23@if18 UP             fe80::fc36:adff:xxxx:xxxx/64
vethecf0d6f@if38 UP             fe80::c8a6:48ff:xxxx:xxxx/64

How can I know which software created those?

You are running docker, which has tons of bridges and virtual devices, depending on how you configure it. As they are down, they may be "leftovers". The lxcbr0 bridge is probably from some LXC containers? — dirkt, Mar 05 '22 at 07:10

Z0OM · Accepted Answer · 2022-03-09T07:31:35.763

5

Your list looks like:

lo = loopback
enp7s0 = ethernet
lp5s0 = wlan
virbr* = virtual bridge
lxcbr* = lxc/lxd
docker* = docker
br* = docker bridge
veth* = virtual Ethernet devices

you can use the nmcli(network manager)

and run:

$ nmcli device list

for your docker containers run:

$ docker network ls

than

$ docker network inspect [USE THE NETWORK ID FROM THE FIRST COMMAND]

try this to to get a list of the network devices:

$ echo /sys/class/net/*

You can get more informations with udevadm:

$ udevadm info -a -p /sys/class/net/[NETWORK DEVICE NAME]

Example:

$ udevadm info -a -p /sys/class/net/enp0s25

With ip:

$ ip -r link

$ ip -br link

$ ip -br -c link show

$ ip token

$ ip -s -s link show dev docker0

With lshw:

$ lshw -class network

$ lshw -class network -short

Update

Get more informations from this manpages:

man systemd.netdev
man systemd.link
man systemd.network

More detail information with networkctl

$ networkctl

$ networkctl status

$ networkctl status --all

edited Mar 09 '22 at 07:31

answered Mar 05 '22 at 08:37

Z0OM

3,149

3

Documentation of the /sys/class/net//name_assign_type https://github.com/torvalds/linux/blob/master/Documentation/ABI/testing/sysfs-class-net – Z0OM Mar 05 '22 at 09:49
3

ah nice, so that veth is from docker '__') after pruning unused docker (docker network prune) it's all gone – Kokizzu Mar 06 '22 at 04:58
3

@Kokizzu | yes lovely docker :-) there is also the possibility(if you want to go deeper) with "linux network namespace interfaces and devices" https://man7.org/linux/man-pages/man8/ip-netns.8.html and https://man7.org/linux/man-pages/man7/network_namespaces.7.html – Z0OM Mar 06 '22 at 11:11

What are these unexpected network devices which appear in kernel log?

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