[Ubuntu-PT 5172] Re: internet mais lenta

[( ``-_-´´ ) -- Fernando]

Olá mota e a todos.

On Tuesday 21 October 2008 15:29:39 mota wrote:
> Reparei que tenho a net mais lenta no ubuntu do que no XP...
> 
> tem estado normal, mas ultimamente tenho notado isso...não sei se foi na
> mudança de kernel, mas ja experimentei velocímetros em ambos os kernels
> e no XP e tenho a net mais rápida no windows...

Desculpem la tar a resucitar uma thread tao antiga, mas ao ler os release notes deparai me com isto:
http://www.ubuntu.com/getubuntu/releasenotes/810

Other known issues
TCP timestamps

Linux 2.6.27 now sets the timestamps option in TCP packets (RFC 1323), an option dating from 1992 to improve performance over high-bandwidth-times-latency paths and to improve reliability over high-bandwidth paths, which was previously omitted by mistake.

However, this change appears to cause problems for some users, believed to be due to buggy routers between the user and the destination server (for example, this has been reported by several Verizon DSL users). If your Internet connection mostly appears to be working correctly, but you have problems connecting to certain sites, then try the following command:

sudo sysctl -w net.ipv4.tcp_timestamps=0

This change will normally expire the next time you restart your computer. If it fixes the problem, then you can make the change permanent by running sudo editor /etc/sysctl.conf and adding the following line to the end of that file:

net.ipv4.tcp_timestamps = 0

The real bug here is in your router (if you own one) or your ISP's routers. If a firmware upgrade is available for your router, follow your manufacturer's instructions to upgrade it. Otherwise, contact the support department of your router manufacturer or your ISP for further advice. At the same time, Linux kernel upstream is investigating a workaround that will restore interoperability with these routers while permitting TCP timestamps to be enabled, and this fix will be evaluated for inclusion in a Stable Release Update after the 8.10 release.

See bug #264019, and thanks to Mandriva for their clear documentation of this issue. 

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