A slightly longer session: $ ip link 1: lo: mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT qlen 1000 link/ether 5c:26:0a:7a:26:34 brd ff:ff:ff:ff:ff:ff 3: eth1: mtu 1500 qdisc pfifo_fast state DORMANT mode DORMANT qlen 1000 link/ether d0:df:9a:d8:2b:46 brd ff:ff:ff:ff:ff:ff $ ip addr eth0 Command "eth0" is unknown, try "ip addr help". $ sudo mii-tool [sudo] password for stephen: SIOCGMIIPHY on 'eth1' failed: Operation not supported no MII interfaces found $ sudo mii-tool -p eth0 SIOCGMIIPHY on 'eth1' failed: Operation not supported no MII interfaces found $ dmesg | grep wl [ 4.429047] wl: module license 'MIXED/Proprietary' taints kernel. [ 4.464325] INFO @wl_cfg80211_attach : Registered CFG80211 phy $ dmesg | grep eth [ 0.169331] reboot: PCI series board detected. Selecting Dell Latitude E6520-method for reboots. [ 1.238195] e1000e 0000:00:19.0 eth0: (PCI Express:2.5GT/s:Width x1) 5c:26:0a:7a:26:34 [ 1.238199] e1000e 0000:00:19.0 eth0: Intel(R) PRO/1000 Network Connection [ 1.238256] e1000e 0000:00:19.0 eth0: MAC: 10, PHY: 11, PBA No: 4041FF-0FF [ 4.084864] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [ 4.550907] eth1: Broadcom BCM4727 802.11 Hybrid Wireless Controller 6.20.155.1 (r326264) [ 5.874878] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [ 5.875343] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready $ service networking restart stop: Rejected send message, 1 matched rules; type="method_call", sender=":1.47" (uid=1000 pid=2853 comm="stop networking ") interface="com.ubuntu.Upstart0_6.Job" member="Stop" error name="(unset)" requested_reply="0" destination="com.ubuntu.Upstart" (uid=0 pid=1 comm="/sbin/init") start: Rejected send message, 1 matched rules; type="method_call", sender=":1.48" (uid=1000 pid=2850 comm="start networking ") interface="com.ubuntu.Upstart0_6.Job" member="Start" error name="(unset)" requested_reply="0" destination="com.ubuntu.Upstart" (uid=0 pid=1 comm="/sbin/init") $ sudo service networking restart networking stop/waiting networking start/running $ sudo mii-tool SIOCGMIIREG on eth0 failed: Input/output error SIOCGMIIREG on eth0 failed: Input/output error eth0: negotiated 100baseTx-FD flow-control, link ok SIOCGMIIPHY on 'eth1' failed: Operation not supported $ ip addr show dev eth0 2: eth0: mtu 1500 qdisc pfifo_fast state DOWN qlen 1000 link/ether 5c:26:0a:7a:26:34 brd ff:ff:ff:ff:ff:ff $ sudo dhclient -v eth0 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0/5c:26:0a:7a:26:34 Sending on LPF/eth0/5c:26:0a:7a:26:34 Sending on Socket/fallback DHCPREQUEST of 192.168.1.3 on eth0 to 255.255.255.255 port 67 (xid=0x11a90ba0) DHCPREQUEST of 192.168.1.3 on eth0 to 255.255.255.255 port 67 (xid=0x11a90ba0) DHCPREQUEST of 192.168.1.3 on eth0 to 255.255.255.255 port 67 (xid=0x11a90ba0) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 (xid=0x114990e3) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6 (xid=0x114990e3) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 11 (xid=0x114990e3) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 17 (xid=0x114990e3) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 9 (xid=0x114990e3) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 15 (xid=0x114990e3) DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 15 (xid=0x114990e3) ^C