The network ip command
Date: 2022-09-19Last modified: 2023-02-17
Route
$ ip route
default via 192.168.15.1 dev wlp3s0 proto dhcp metric 600
10.181.29.0/24 dev lxdbr0 proto kernel scope link src 10.181.29.1 linkdown
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
192.168.15.0/24 dev wlp3s0 proto kernel scope link src 192.168.15.19 metric 600
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
DESTINATION |INTERFACE |PROTOCOL | |SOURCE |
After launching 5 lxc containers we can realize that each one use an specific virtual interface.
$ ip route
default dev vethb1efb2e9 scope link
default via 192.168.15.1 dev wlp3s0 proto dhcp metric 600
10.181.29.0/24 dev lxdbr0 proto kernel scope link src 10.181.29.1
169.254.0.0/16 dev vethb1efb2e9 proto kernel scope link src 169.254.249.217
169.254.0.0/16 dev vetha30d7f12 proto kernel scope link src 169.254.153.8
169.254.0.0/16 dev veth21ef1dfb proto kernel scope link src 169.254.28.175
169.254.0.0/16 dev vethcfed8118 proto kernel scope link src 169.254.129.246
169.254.0.0/16 dev vethdf8caaa2 proto kernel scope link src 169.254.206.4
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
192.168.15.0/24 dev wlp3s0 proto kernel scope link src 192.168.15.19 metric 600
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
After reconfiguring lxc bridge lxdbr0 to use the address 10.11.12.254 we
get and inconsistent routing table.
$ ip route
default dev veth36479aca scope link
default via 192.168.15.1 dev wlp3s0 proto dhcp metric 600
10.11.12.0/24 dev lxdbr0 proto kernel scope link src 10.11.12.254
169.254.0.0/16 dev veth36479aca proto kernel scope link src 169.254.129.244
169.254.0.0/16 dev veth53f1f182 proto kernel scope link src 169.254.80.31
169.254.0.0/16 dev vethe35f1309 proto kernel scope link src 169.254.67.125
169.254.0.0/16 dev veth252db3c5 proto kernel scope link src 169.254.17.212
169.254.0.0/16 dev vethd2deb052 proto kernel scope link src 169.254.199.118
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
192.168.15.0/24 dev wlp3s0 proto kernel scope link src 192.168.15.19 metric 600
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown
Another problem is the default gateway was replaced by a virtual interface and my host can’t resolve any internet address. To solve this issue I set the correct gateway again.
ip route del default
route add default gw 192.168.15.1 dev wlp3s0
Then setting the containers to use the bridge
$ ip route
default via 192.168.15.1 dev wlp3s0
default via 192.168.15.1 dev wlp3s0 proto dhcp metric 600
10.11.12.0/24 dev lxdbr0 proto kernel scope link src 10.11.12.254
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown
192.168.15.0/24 dev wlp3s0 proto kernel scope link src 192.168.15.19 metric 600
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1 linkdown