Je précise juste que j'ai installé xubuntu 18.04 en double boot, et que je ne fonctionne plus en live session.
lorsque je relance les commandes conseillées, et que je relance ifconfig -a, j'obtiens :
enp0s15: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether 00:19:99:76:27:39 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
enp0s15:avahi: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 169.254.5.103 netmask 255.255.0.0 broadcast 169.254.255.255
ether 00:19:99:76:27:39 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Boucle locale)
RX packets 1337 bytes 81977 (81.9 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1337 bytes 81977 (81.9 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
mais toujours pas de connexion à internet.