linux - Ethernet interface 'em1' not allowing connection

06
2014-04

BenjiWiebe

Why does my network interface 'em1' (the onboard ethernet) not allow NetworkManager to do anything with it? It also doesn't seem to work to use ip addr add to add an IP to it.

With my laptop plugged in via Ethernet: ifconfig em1 outputs:

em1: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 00:13:d3:5b:cf:88  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

What should I check next? I have already made sure that the cable I am using works. Laptop<-Wired->Router works, but PossiblyBadInterface<-Wired->Router doesn't. Therefore it must be the interface that has problems. But I don't know how to troubleshoot it. Any suggestions?

Oh, also, sudo ifup em1 shows:

Error: Connection activation failed: Device not managed by NetworkManager or unavailable

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Related Question

linux - Unable to connect to wired internet connection using Ubuntu

linux ubuntu-10.04 lan

macha

Hello I am unable to connect to the Internet using a wired connection. I was able to use the wired network yesterday. But I had problems with the flash player, so had to reinstall Ubuntu again. I am able to connect to Internet using wireless connection. But I need to connect to the wired connection. I am using Ubuntu 10. In my IPv4 settings, it is automatically set to DHCP, using which, I was earlier able to connect. But now it doesn't seem to be happening.

$ ifconfig
eth0      Link encap:Ethernet  HWaddr 18:a9:05:22:cd:f9  
          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:28 Base address:0x4000 

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:16436  Metric:1
          RX packets:108 errors:0 dropped:0 overruns:0 frame:0
          TX packets:108 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:8272 (8.2 KB)  TX bytes:8272 (8.2 KB)

wlan0     Link encap:Ethernet  HWaddr 00:26:82:3c:ac:27  
          inet addr:192.168.1.102  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::226:82ff:fe3c:ac27/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:204253 errors:0 dropped:0 overruns:0 frame:0
          TX packets:107610 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:299528765 (299.5 MB)  TX bytes:10274020 (10.2 MB)

Hey but there are other entries on the syslog that were recent.

Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>  DHCP: device wlan0 state changed preinit -> bound
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) Stage 4 of 5 (IP4 Configure Get) scheduled...
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) Stage 4 of 5 (IP4 Configure Get) started...
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>    address 192.168.1.105
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>    prefix 24 (255.255.255.0)
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>    gateway 192.168.1.1
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>    nameserver '192.168.1.1'
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) Stage 5 of 5 (IP Configure Commit) scheduled...
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) Stage 4 of 5 (IP4 Configure Get) complete.
Aug 26 09:35:15 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) Stage 5 of 5 (IP Configure Commit) started...
Aug 26 09:35:15 saisriparasa-desktop avahi-daemon[902]: Joining mDNS multicast group on interface wlan0.IPv4 with address 192.168.1.105.
Aug 26 09:35:15 saisriparasa-desktop avahi-daemon[902]: New relevant interface wlan0.IPv4 for mDNS.
Aug 26 09:35:15 saisriparasa-desktop avahi-daemon[902]: Registering new address record for 192.168.1.105 on wlan0.IPv4.
Aug 26 09:35:16 saisriparasa-desktop NetworkManager: <info>  (wlan0): device state change: 7 -> 8 (reason 0)
Aug 26 09:35:16 saisriparasa-desktop NetworkManager: <info>  Policy set 'Auto OEGLLC' (wlan0) as default for routing and DNS.
Aug 26 09:35:16 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) successful, device activated.
Aug 26 09:35:16 saisriparasa-desktop NetworkManager: <info>  Activation (wlan0) Stage 5 of 5 (IP Configure Commit) complete.

Output of dhclient

Listening on LPF/eth0/18:a9:05:22:cd:f9 
Sending on LPF/eth0/18:a9:05:22:cd:f9 
Listening on LPF/wlan0/00:26:82:3c:ac:27 
Sending on LPF/wlan0/00:26:82:3c:ac:27 
Sending on Socket/fallback 
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 8 
DHCPOFFER of 192.168.1.105 from 192.168.1.1 
DHCPREQUEST of 192.168.1.105 on wlan0 to 255.255.255.255 port 67 
DHCPACK of 192.168.1.105 from 192.168.1.1 
bound to 192.168.1.105 -- renewal in 35073 seconds

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linux - Ethernet interface 'em1' not allowing connection