This is Server2308 (I call it m4). I edited /etc/network/interfaces Then I rebooted the server. Then I ran the commands bellow. The interesting part is that "ethtool p4p1" reports: Speed: Unknown! Duplex: Unknown! (255) Link detected: no This is the case for all servers, not only Server2308 which I use in this example. So I wonder: What model is the switch? Is the switch turned on? Is the cable actually connected? Is the cable connected to p4p1 (82574L Gigabit Network Connection) or is it connected elsewhere? Do you have any ideas what could be wrong? $ ssh root@m4 Welcome to Ubuntu 13.04 (GNU/Linux 3.8.0-19-generic x86_64) * Documentation: https://help.ubuntu.com/ System information as of Thu May 23 06:45:36 CDT 2013 System load: 0.0 Processes: 138 Usage of /: 0.7% of 197.63GB Users logged in: 0 Memory usage: 0% IP address for em1: 23.29.122.162 Swap usage: 0% IP address for p4p1: 192.168.1.4 Graph this data and manage this system at https://landscape.canonical.com/ 8 packages can be updated. 7 updates are security updates. Last login: Thu May 23 06:28:48 2013 from s83-177-171-150.cust.tele2.se root@m4:~# cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto em1 iface em1 inet static address 23.29.122.162 netmask 255.255.255.248 network 23.29.122.160 broadcast 23.29.122.167 gateway 23.29.122.161 # dns-* options are implemented by the resolvconf package, if installed dns-nameservers 8.8.8.8 dns-search yourdomain.com # internal auto p4p1 iface p4p1 inet static address 192.168.1.4 netmask 255.255.255.0 root@m4:~# ifconfig em1 Link encap:Ethernet HWaddr 00:25:90:78:5f:7b inet addr:23.29.122.162 Bcast:23.29.122.167 Mask:255.255.255.248 inet6 addr: fe80::225:90ff:fe78:5f7b/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:12843 errors:0 dropped:0 overruns:0 frame:0 TX packets:2154 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1746154 (1.7 MB) TX bytes:300121 (300.1 KB) Interrupt:20 Memory:dfa00000-dfa20000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:173 errors:0 dropped:0 overruns:0 frame:0 TX packets:173 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:13606 (13.6 KB) TX bytes:13606 (13.6 KB) p4p1 Link encap:Ethernet HWaddr 00:25:90:78:5f:7a inet addr:192.168.1.4 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:16 Memory:df900000-df920000 root@m4:~# ethtool em1 Settings for em1: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 2 Transceiver: internal Auto-negotiation: on MDI-X: off Supports Wake-on: pumbg Wake-on: g Current message level: 0x00000007 (7) drv probe link Link detected: yes root@m4:~# ethtool -i em1 driver: e1000e version: 2.1.4-k firmware-version: 0.13-4 bus-info: 0000:00:19.0 supports-statistics: yes supports-test: yes supports-eeprom-access: yes supports-register-dump: yes supports-priv-flags: no root@m4:~# dmesg | grep -i em1 [ 1.969682] IPv6: ADDRCONF(NETDEV_UP): em1: link is not ready [ 4.782530] e1000e: em1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx [ 4.782563] IPv6: ADDRCONF(NETDEV_CHANGE): em1: link becomes ready root@m4:~# ethtool p4p1 Settings for p4p1: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Speed: Unknown! Duplex: Unknown! (255) Port: Twisted Pair PHYAD: 1 Transceiver: internal Auto-negotiation: on MDI-X: Unknown Supports Wake-on: pumbg Wake-on: g Current message level: 0x00000007 (7) drv probe link Link detected: no root@m4:~# ethtool -i p4p1 driver: e1000e version: 2.1.4-k firmware-version: 2.1-2 bus-info: 0000:02:00.0 supports-statistics: yes supports-test: yes supports-eeprom-access: yes supports-register-dump: yes supports-priv-flags: no root@m4:~# dmesg | grep -i p4p1 [ 1.714513] IPv6: ADDRCONF(NETDEV_UP): p4p1: link is not ready root@m4:~# lspci | egrep -i --color 'network|ethernet' 00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 05) 02:00.0 Ethernet controller: Intel Corporation 82574L Gigabit Network Connection root@m4:~# lshw -C network *-network description: Ethernet interface product: 82579LM Gigabit Network Connection vendor: Intel Corporation physical id: 19 bus info: pci@0000:00:19.0 logical name: em1 version: 05 serial: 00:25:90:78:5f:7b size: 1Gbit/s capacity: 1Gbit/s width: 32 bits clock: 33MHz capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.1.4-k duplex=full firmware=0.13-4 ip=23.29.122.162 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s resources: irq:40 memory:dfa00000-dfa1ffff memory:dfa25000-dfa25fff ioport:f020(size=32) *-network description: Ethernet interface product: 82574L Gigabit Network Connection vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: p4p1 version: 00 serial: 00:25:90:78:5f:7a capacity: 1Gbit/s width: 32 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.1.4-k firmware=2.1-2 ip=192.168.1.4 latency=0 link=no multicast=yes port=twisted pair resources: irq:16 memory:df900000-df91ffff ioport:e000(size=32) memory:df920000-df923fff root@m4:~#