Hi all,
I would like to force the LAN card to use 10MB instead of 100MB in UNIX enviroment, please help. thanks! 
use this script:
http://docs.cirkva.net/Sun/Solaris/Eis/S68net-tune
read the first few lines on how to use it!
box[root]# ndd -get /dev/ce \?
? (read only)
instance (read and write)
adv_autoneg_cap (read and write)
adv_1000fdx_cap (read and write)
adv_1000hdx_cap (read and write)
adv_100T4_cap (read and write)
adv_100fdx_cap (read and write)
adv_100hdx_cap (read and write)
adv_10fdx_cap (read and write)
adv_10hdx_cap (read and write)
adv_asmpause_cap (read and write)
adv_pause_cap (read and write)
master_cfg_enable (read and write)
master_cfg_value (read and write)
use_int_xcvr (read and write)
enable_ipg0 (read and write)
ipg0 (read and write)
ipg1 (read and write)
ipg2 (read and write)
rx_intr_pkts (read and write)
rx_intr_time (read and write)
red_dv4to6k (read and write)
red_dv6to8k (read and write)
red_dv8to10k (read and write)
red_dv10to12k (read and write)
tx_dma_weight (read and write)
rx_dma_weight (read and write)
infinite_burst (read and write)
disable_64bit (read and write)
accept_jumbo (read and write)
laggr_multistream (read and write)
/dev/ce adv_10hdx_cap -- half dup
/dev/ce adv_10fdx_cap --full dup
box[root]# ndd -get /dev/ce adv_10hdx_cap
0
box[root]# ndd -get /dev/ce adv_10fdx_cap
0
use ndd to set it to 1, read man pages how to use ndd. Then add the ndd command into S99ndd in rc3.d so everything it reboot it will set to 10m
Thanks DukeNuke2 & sparcguy. The solution works.