> I have a really weird problem with some of my servers, namely all the > ones running Centos5 > > When I try to download a file from the server to a machine outside our > Cisco 6500 router/firewall, the download hangs about half the times > (15 out of 40) when less than half a megabyte into the transfer > (varied from 76 kb to 496 kb). > > One server has a portchannel (Cisco speak for ethernet bundle), others > do not, some use e1000, some use broadcom, I've tried httpd and scp > transfers, I've tried from three different clients, > > Here's the really annoying part: the problem only occurs when > downloading from outside the firewall, not when transferring files > internally in the serverroom! And the switch is the firewall is a > modular chassis, so the data comes over the same backplane regardless. > > And there's 42 files in /proc/net/sys/ipv4 which differ between EL4 > and Centos5, so I'm a little lost here I don't know if this would help, but I remember reading a post about a problem with tcp window scaling. To disable tcp window scaling add the line net.ipv4.tcp_window_scaling = 0 to /etc/sysctl.conf and then run sysctl -p to activate your change. Barry