Hello I experienced strange problem with bandwith. My CentOS 4.3 x86_64 server is a gateway to Internet. The uplink is 20 Mbps full duplex Eth card is part of NForce4 chipset, the module is "forcedeth" As a testing tool we use "iperf" http://dast.nlanr.net/Projects/Iperf/ By test we decide downloda is only 10 Mbps (upload is 18-20 Mbps) The first suspect was ISP, so we did test in cooperation. ISP Our site FreeBSD ========= FreeBSD (ISP test machine) TCP&UDP down 20 Mbps TCP&UDP up 20 Mbps TCP&UDP up 20 Mbps TCP&UDP down 20 Mbps result: link is Ok The second and final suspect was our gateway: ISP Our site FreeBSD ========= CentOS 4.3 UDP down 20 Mbps UDP up 20 Mbps UDP up 20 Mbps UDP down 20 Mbps BUT TCP down 20 Mbps TCP up 20 Mbps TCP up 10-12 Mbps TCP down 10-12 Mbps SO: there is an problem with TCP ??? At the time of testing there was NO iptable rules or shaping enabled ... Where to find? I realy do not know. Petr Klíma e-mail: qaxi at seznam.cz