To check duplex and speed on the Smoothwall:

#ethtool ethA (always recommended to set the auto-negotiate on the switch side for the interface where Smoothwall is connected)

(for example to change the MTU size on the fly for testing purposes) (Shows the network speed and information about the interface)

To change the speed, duplex and the auto-negotiate for an interface:

#ethtool -s ethX speed 100 duplex full autoneg off (to turn off the auto negotiate)

OR

#vi /etc/actions/secondboot/9999custom

(insert the following in the file)

#! /bin/sh

/usr/sbin/ethtool -s ethC duplex full speed 100 autoneg off

(now press escape :wq! )

#chmod +x /etc/actions/secondboot/9999custom

#/etc/actions/secondboot/9999custom

(Finally, you need to reboot to exectute the startup script created, if required)