Install iperf client on windows from:
or
Ubuntu using:
sudo apt-get install iperf
Try the following from the client machines inside the network and/or from the Smoothwall:
(using speedtest sites through the Smoothwall are not recommended)
iperf -c iperf.securityinspection.com
iperf -c iperf.saratov.ertelecom.ru
iperf -c st2.nn.ertelecom.ru
iperf -c iperf.ips.versatel.de
iperf -c iperf.testdebit.info
iperf -c iperf.cds.com
iperf -c iperf.lan.kth.se
(More servers can be found here: http://en.wikipedia.org/wiki/Iperf)