A.DDN B.NII C.CERNET D.CHINANET
A.路由器故障 B.網(wǎng)卡驅(qū)動(dòng)故障或丟失 C.網(wǎng)卡被禁用 D.網(wǎng)卡硬件故障
A.HTTP B.FTP C.SMTP D.DHCP