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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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Could you post the output of ifconfig -a –  BloodPhilia Aug 26 '10 at 14:10
    
Can you give us more details? Do you unplug your wireless router, to use the wired connection the router used? Do you use DSL or perhaps WAN? –  trolle3000 Aug 26 '10 at 14:12
    
I just use regular wired connection, one end is connected to my pc and another to the router. I also tested that with my co-worker, he used my the same connection I use and he was able to get internet. –  macha Aug 26 '10 at 14:17
    
Is the ifconfig made with the cable connected? –  BloodPhilia Aug 26 '10 at 14:18
    
yes the cable is connected presently. –  macha Aug 26 '10 at 14:19

2 Answers 2

up vote 1 down vote accepted

Check the output of 'dmesg | tail' just after you have connected the cable. It should show a message about eth0. Also check to see that a dhcp client is running using 'ps -ef | grep dhc' just after you connect the cable.

If you have a /etc/network/interfaces definition for eth0, try the commands "ifdown eth0" followed by "ifup eth0" with the cable plugged in. This should give you an ip address. You could comment out the whole block for eth0 in /etc/network/interfaces and reconnect the cable to use the network-manager configuration. Network-manager ignores ports handled by /etc/network/interfaces.

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root 2126 1 0 09:47 ? 00:00:00 dhclient root 2155 915 0 09:48 ? 00:00:00 /sbin/dhclient -d -sf /usr/lib/NetworkManager/nm-dhcp-client.action -pf /var/run/dhclient-wlan0.pid -lf /var/lib/dhcp3/dhclient-393ada0a-baed-4929-a2ff-170f604eb242-wlan0.lease -cf /var/run/nm-dhclient-wlan0.conf wlan0 1000 2254 1822 0 09:55 pts/0 00:00:00 grep --color=auto dhc is the output of 'ps -ef|grep dhc' –  macha Aug 26 '10 at 14:56
    
Output for ifdown eth0 is saisriparasa@saisriparasa-desktop:~$ sudo ifdown eth0 ifdown: interface eth0 not configured It says it is not configured? –  macha Aug 26 '10 at 14:57
    
auto lo iface lo inet loopback This is all I got in /etc/network/interfaces file –  macha Aug 26 '10 at 14:58
    
/etc/network interfaces doesn't seem to be configured. Open network manager and verify that it has eth0. Also it looks like you have a wireless connection up. This might interfere with the wired connection. –  BillThor Aug 27 '10 at 15:56

Might seem silly, but the first thing you should check is that the cable is plugged in firmly at both ends.

share|improve this answer
    
Yes, and another friend of mine was getting internet when he plugged to the cable I am using. –  macha Aug 26 '10 at 14:17

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