On 09/03/2016 03:08 AM, sunyeping wrote: > But when I give "ifconfig" command in a gnome terminal, the output information seems to be correct: > > [sunyp at localhost Desktop]$ ifconfig > ... > eth1 Link encap:Ethernet HWaddr 00:25:90:72:E2:87 > inet6 addr: fe80::225:90ff:fe72:e287/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:49 errors:0 dropped:0 overruns:0 frame:0 > TX packets:11 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:16386 (16.0 KiB) TX bytes:3038 (2.9 KiB) > Interrupt:17 Memory:fafe0000-fb000000 You don't have any valid IPv4 or IPv6 addresses. Normally those things are provided by your router. Check your cabling first. Then check your router's logs to see if it's getting DHCP requests from your desktop.