While I use “ifconfig” ,it shows that
lo0: flags=8009<UP,LOOPBACK,MULTICAST> mtu 33212
capabilities=7<IP4CSUM,TCP4CSUM,UDP4CSUM>
enabled=0<>
inet 127.0.0.1 netmask 0xff000000
It seems that I don’t install network driver. 
Here is the info of my network card
Accton EN1207F Series PCI Fast Ethernet Adapter.
Could anyone tell me how to find the driver and install the device?
thanls a lot!!! 
It might be a rtl or tulip.
try
io-net -d rtl -ptcpip &
or
io-net -d tulip -ptcpip &
and then try “ifconfig -a” again.
post “pci -v” if still not work.
Thanks for your help
I try all the driver.But No driver works. 
Whlie I change the network
card(Reltek8139),it works.
Why ??? It makes me confused.
Here is my pci-v information about Accton EN5251 Enthernet.
Class = Network (Ethernet)
Vendor ID = 1113h, Accton Technology Corporation
Device ID = 1216h, EN5251 Ethernet Controller
PCI index = 0h
Class Codes = 020000h
Revision ID = 11h
Bus number = 2
Device number = 10
Function num = 0
Status Reg = 290h
Command Reg = 17h
Header type = 0h Single-function
BIST = 0h Build-in-self-test not supported
Latency Timer = 20h
Cache Line Size= 8h un-cacheable
PCI IO Address = b400h length 256 enabled
PCI Mem Address = ed000000h 32bit length 1024 enabled
Subsystem Vendor ID = 1113h
Subsystem ID = 1216h
Max Lat = 255ns
Min Gnt = 255ns
PCI Int Pin = INT A
Interrupt line = 5
Capabilities Pointer = c0h
Capability ID = 1h
Capabilities = fe82h - 0h
From what I could find, the Accton Tech EN5251 is a Centaur chipset and “should” work with the tulip driver. You may have to start it with:
io-net -dtulip did=0x1216,vid=0x1113 -ptcpip
and see if that helps. If not, you are probably out of luck… Apparently these cards took updated tulip drivers for linux, so it is possible that it is not really compatible.
If you have a working realtek card, then use that.