Comments on: TCP Window Scaling and kernel 2.6.17+ http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/ Moo - Development, Trouble-shooting and Random thoughts... Fri, 21 Nov 2008 00:50:09 +0000 http://wordpress.org/?v=2.6 By: linsec.ca blog » Blog Archive » Welcome back, kernel 2.6.17+ http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-2399 linsec.ca blog » Blog Archive » Welcome back, kernel 2.6.17+ Tue, 25 Mar 2008 19:18:23 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-2399 [...] Due to an issue that the 2.6.17+ kernel exemplified, all of the sites I host (annvix.org, linsec.ca, danen.ca, etc.) have been unavailable to anyone using a 2.6.17+ kernel due to a change in the way TCP window scaling was implemented, which has been noted in a number of places (here’s one: TCP Window Scaling and kernel 2.6.17+). [...] [...] Due to an issue that the 2.6.17+ kernel exemplified, all of the sites I host (annvix.org, linsec.ca, danen.ca, etc.) have been unavailable to anyone using a 2.6.17+ kernel due to a change in the way TCP window scaling was implemented, which has been noted in a number of places (here’s one: TCP Window Scaling and kernel 2.6.17+). [...]

]]> By: Grant Carmichael » Blog Archive » Is your Linux box running slow behind your firewall? http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-2320 Grant Carmichael » Blog Archive » Is your Linux box running slow behind your firewall? Thu, 31 Jan 2008 19:47:18 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-2320 [...] First read the following articles: [...] [...] First read the following articles: [...]

]]> By: chouse http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-2318 chouse Wed, 30 Jan 2008 20:47:47 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-2318 Totally solved my issue with RHEL5. Big thanks. Totally solved my issue with RHEL5. Big thanks.

]]> By: sathish http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-1610 sathish Mon, 13 Aug 2007 04:52:02 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-1610 How to turn off windows scaling on windows xp pc How to turn off windows scaling on windows xp pc

]]> By: bizarre lack of HTTP response problem - Page 2 - Linux Forums http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-1293 bizarre lack of HTTP response problem - Page 2 - Linux Forums Fri, 29 Jun 2007 06:58:51 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-1293 [...] explanation / workaround Recently I found out what is going on with this bug. The problem has to do with larger default buffer sizes for TCP window scaling in recent Linux kernel versions. If there is an improperly configured router between you and the server you're trying to reach, it will create a bottleneck and you'll get no data from the server. The long and the short of it is that it is not a Linux bug. Here are some better, more detailed explanations: John’s Tidbits » Blog Archive » TCP Window Scaling and kernel 2.6.17+ Linux: Window Scaling on the Internet | KernelTrap The solution I have used (and I've had to do it again whenever I've updated my kernel) is to change the values in /proc/sys/net/ipv4/tcp_wmem and /proc/sys/net/ipv4/tcp_rmem. The new values should be "4096 16384 131072" and "4096 87380 174760" respectively. This sets the window scaling buffer back to its earlier/smaller size. [...] [...] explanation / workaround Recently I found out what is going on with this bug. The problem has to do with larger default buffer sizes for TCP window scaling in recent Linux kernel versions. If there is an improperly configured router between you and the server you’re trying to reach, it will create a bottleneck and you’ll get no data from the server. The long and the short of it is that it is not a Linux bug. Here are some better, more detailed explanations: John’s Tidbits » Blog Archive » TCP Window Scaling and kernel 2.6.17+ Linux: Window Scaling on the Internet | KernelTrap The solution I have used (and I’ve had to do it again whenever I’ve updated my kernel) is to change the values in /proc/sys/net/ipv4/tcp_wmem and /proc/sys/net/ipv4/tcp_rmem. The new values should be "4096 16384 131072" and "4096 87380 174760" respectively. This sets the window scaling buffer back to its earlier/smaller size. [...]

]]> By: infotage.net » Blog Archive » Debian ip stack tuning http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-391 infotage.net » Blog Archive » Debian ip stack tuning Sat, 17 Mar 2007 01:58:58 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-391 [...] http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/ [...] [...] http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/ [...]

]]> By: The Adventures of Slightly Taller Than Average Man » Fedora kernel upgrade caused excruciatingly slow network speeds http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-346 The Adventures of Slightly Taller Than Average Man » Fedora kernel upgrade caused excruciatingly slow network speeds Mon, 05 Mar 2007 09:20:37 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-346 [...] Googling found nothing, so I had to grin and bear it until the sysadmin found a fix.  After a while, he came across this solution (from here). echo 0 > /proc/sys/net/ipv4/tcp_window_scaling [...] [...] Googling found nothing, so I had to grin and bear it until the sysadmin found a fix.  After a while, he came across this solution (from here). echo 0 > /proc/sys/net/ipv4/tcp_window_scaling [...]

]]> By: Murray http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-49 Murray Thu, 23 Nov 2006 05:53:53 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-49 Another way... vi /etc/sysctl.conf add the following two lines net.ipv4.tcp_wmem = 4096 16384 131072 net.ipv4.tcp_rmem = 4096 87380 174760 sysctl -p Another way…

vi /etc/sysctl.conf

add the following two lines

net.ipv4.tcp_wmem = 4096 16384 131072
net.ipv4.tcp_rmem = 4096 87380 174760

sysctl -p

]]> By: GNEMAN http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-32 GNEMAN Thu, 28 Sep 2006 04:11:18 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-32 The argument that they shouldn't workaround the window scaling problem because there shouldn't be broken boxes out there in the first place is just like saying that we shouldn't have jails becasue people shouldn't be doing illegal things in the first place. Yes, in an ideal world that's correct. But we don't live in an ideal world. People do illegal things, so we need jails. And there are broken boxes out there, so we need workarounds. The day no one does any illegal thing will be the day to get rid of jails, not before. And the day there are no broken boxes out there, we can use this new window scaling value. It's simple. Now when most big distros move to kernel 2.6.17 (just in the next month or 2) we'll have thousands of people complaining that their connection doesn't work. And nobody will know or care about window scaling. They'll just want their computer to work as it did before. Oops, sorry for the rant. It's not aimed at you, of course. I just thought I would post my thoughts about this issue here in case Linux Torvalds reads this blog :) The argument that they shouldn’t workaround the window scaling problem because there shouldn’t be broken boxes out there in the first place is just like saying that we shouldn’t have jails becasue people shouldn’t be doing illegal things in the first place. Yes, in an ideal world that’s correct. But we don’t live in an ideal world. People do illegal things, so we need jails. And there are broken boxes out there, so we need workarounds. The day no one does any illegal thing will be the day to get rid of jails, not before. And the day there are no broken boxes out there, we can use this new window scaling value. It’s simple. Now when most big distros move to kernel 2.6.17 (just in the next month or 2) we’ll have thousands of people complaining that their connection doesn’t work. And nobody will know or care about window scaling. They’ll just want their computer to work as it did before.

Oops, sorry for the rant. It’s not aimed at you, of course. I just thought I would post my thoughts about this issue here in case Linux Torvalds reads this blog :)

]]> By: johnf http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-4 johnf Wed, 06 Sep 2006 22:16:16 +0000 http://inodes.org/blog/2006/09/06/tcp-window-scaling-and-kernel-2617/#comment-4 Thanks, fixed now. Thanks, fixed now.

]]>