[U-Boot] Ping is not working with uboot 1.3.4 on at91sam9263 custom board

Hi i have been using custom board with at91sam9263 and U boot 1.3.4, It showing that link is up and down whenever i pluging and plugout the Ethernet cable. But when I try to ping, it showing : host device not active. Whether its a problem with Uboot or something with board?? Your suggestions would be great help for me.