If the IP is static, you need to provide one. You can do:
ifconfig eth0 192.168.1.5 netmask 255.255.255.0 up
And then set a default gateway:
route add -net 0.0.0.0 gw 192.168.1.1
That said, only examples, replace by anything you have configured in your network...
Marcelo Soares