Hello Michael, If you are sure that this is not a hardware problem. This might be a ECN(Explicit Congestion Notification) or window scaling issue. A router on your path or your gateway is ignoring window scaling or does not support ECN. The Ubuntu machine is retransmitting a lot, that's why you are experiencing slow image and or webpage rendering.
Windows XP has windows scaling on by default but does not do auto-tuning which is done in Linux through the tcp_moderate_rcvbuf sysctl switch. Try setting these sysctl switches in order, do not set all at once: net.ipv4.tcp_moderate_rcvbuf to 0 net.ipv4.tcp_workaround_signed_windows to 1 net.ipv4.tcp_window_scaling to 0 net.ipv4.tcp_timestamps to 0 net.ipv4.tcp_ecn to 0 Although very unlikely, it's also possible that the Ubuntu machine has unworkable values on these sysctl switches: net.ipv4.tcp_adv_win_scale and net.ipv4.tcp_rmem. I said unlikely because I presume the Ubuntu machine is a default install and no changes to sysctl switches were done. If it's your gateway or a box your organization controls that is causing it, I suggest replacing it as soon as possible. Sooner or later you will hit this problem again since most of the new operating systems has receive window auto-tuning or dynamic right sizing on by default. See the following : <http://www.microsoft.com/technet/technetmag/issues/2007/01/CableGuy/default.aspx> <http://developer.osdl.org/~shemminger/LWE2005_TCP.pdf> Cheers, pǝ On 9/6/07, Michael Tinsay <[EMAIL PROTECTED]> wrote: > > > I'm in this wierd situation: > > I have two desktops in the same network accessing the Internet via the same > gateway without using any proxy. One is a WinXP machine and the other is > running Ubuntu 7.04 (Feisty). But have no firewall active and have the same > Primary, Secondary (and even Tertiary) DNS servers configured. > > Accessing Yahoo! Mail is no problem in both machines. But while I don't > encounter problem with Y! Mail in the XP machines, in the Ubuntu PC, images > in the email (those that are linked from another site rather than embedded) > are not being loaded completely -- mapapansin mo na sa lahat ng images mga > 25% (topmost part of the images) lang ang nagload. > > Accessing Hotmail, the WinXP machine is able to login properly. The Ubuntu > machine just hangs at "Loading Windows Live Mail". > > In some sites, it takes Ubuntu forever to load completely, in some sites the > web page doesn't load. No problem with the XP machine visiting the same > sites. > > What could be the problem? > > > --- mike t. > > > _________________________________________________ > Philippine Linux Users' Group (PLUG) Mailing List > [email protected] (#PLUG @ irc.free.net.ph) > Read the Guidelines: http://linux.org.ph/lists > Searchable Archives: http://archives.free.net.ph > _________________________________________________ Philippine Linux Users' Group (PLUG) Mailing List [email protected] (#PLUG @ irc.free.net.ph) Read the Guidelines: http://linux.org.ph/lists Searchable Archives: http://archives.free.net.ph
