1) Get the interface name
#ifconfig -a
2)You have number of ways to find the duplex of a NIC card and here are some of them,
The network interface I am using here is bge1
#cat /platform/sun4u/kernel/drv/bge.conf name=”bge” parent=”/pci@780/pci@0/pci@1″ unit-address=”0,1″ adv_autoneg_cap=0 adv_1000fdx_cap=1 adv_1000hdx_cap=0 adv_100fdx_cap=1 adv_100hdx_cap=0 adv_10fdx_cap=0 adv_10hdx_cap=0; or #kstat bge:1 | grep adv adv_cap_1000fdx 1 adv_cap_1000hdx 0 adv_cap_100fdx 1 adv_cap_100hdx 0 adv_cap_100T4 0 adv_cap_10fdx 0 adv_cap_asmpause 0 adv_cap_autoneg 0 adv_cap_pause 0 or # dmesg|grep -i bge Aug 14 10:10:25 testbox1 genunix: [ID 408822 kern.info] NOTICE: bge1: no fault external to device; service available Aug 14 10:10:25 testbox1 genunix: [ID 611667 kern.info] NOTICE: bge1: xcvr addr:0x01 – link up 1000 Mbps full duplex or #dladm show-dev bge1 link: up speed: 1000 Mbps duplex: full or # ndd -get /dev/bge1 adv_100fdx_cap # ndd -get /dev/bge1 adv_1000fdx_cap