my company just start to use streamyx OIAB 4MB recently. the problem im encountered is the upload speed i got is very bad. in my modem configuration i can see my upload speed is 500+ kbps but when i run speedtest i get 0.01mbps and sometime is prompt an error "upload test error".

FYI, my modem (d-link 2640B) is running behind a firewall. i got no problem with my 1MB streamyx enterprise previously (also using d-link modem).

anyone has any idea how to solve this problem?

ok, i've done some troubleshooting today.
disconnect the modem from the firewall, the dl and ul speed is perfect for the LAN and wireless.
connect the modem back to firewall, dl ok but ul problem on LAN. test on wireless, dl and ul speed is perfect.
then i try to connect a new PC (without any IP settings) to the modem on firewall, test on the dl and ul speed is perfect.
remove all IP settings on my laptop, dl ok and ul problem on LAN. test on wireless, dl and ul speed is perfect.

im confused now.