Forcing NIC Speed and Duplex on Solaris 10

There are two ways to force duplex & speed on a Solaris 10 box - via the driver, and via ndd.

First, via the driver:

# cat <<EOD > /platform/`uname -i`/kernel/drv/bge.conf
adv_autoneg_cap=0 adv_1000fdx_cap=0 adv_1000hdx_cap=0
adv_100fdx_cap=1 adv_100hdx_cap=0 adv_10fdx_cap=0
adv_10hdx_cap=0;
EOD

Note that this sets all instances of bge to 100Mbit Full Duplex.

If you wish to be more selective, you can do this:

# cat <<EOD > /etc/init.d/net-tune
#!/bin/sh
# Force to 100FDX
NIC=bge
for i in 0 1 2 3; do
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_1000fdx_cap 0
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_1000hdx_cap 0
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_100fdx_cap 1
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_100hdx_cap 0
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_10fdx_cap 0
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_10hdx_cap 0
  /usr/sbin/ndd -set /dev/${NIC}${i} adv_autoneg_cap 0
done
EOD

# chmod 755 /etc/init.d/net-tune
# ln -s /etc/init.d/net-tune /etc/rc2.d/S68net-tune

You have to reboot for the kernel config file to take effect, but you can run the net-tune script at any time to make it work. You can change the 0 1 2 3 in the for do loop above to set the instances you need.