Bug#401435: debian-installer: sometimes net install does not work because of networking change in Linux 2.6.17 or later

[Josip Rodin <joy@entuzijast.net>]

On Sun, Dec 03, 2006 at 03:14:02PM +0100, Santiago Vila wrote:
> Short summary: A change introduced in Linux 2.6.17 makes the network
> not to work properly in some cases, due to buggy routers.
> 
> There is a trivial workaround:
> 
> echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
> 
> However, I had to spend several afternoons to *diagnose* this problem
> and realize what exactly the nature of the problem was.

I saw this linked from the d-i web page, so I feel I should point out a bit
of an injustice - that workaround is way too severe, as it kills off TCP
window scaling altogether.

TCP window scaling as such was by default enabled in earlier Linux kernel
versions, too, but the default window *sizes* were different, much smaller.
These are set in the tcp_rmem/tcp_wmem pseudo-files in the same directory;
you could just run something like

echo 4096 65536 65536 > /proc/sys/net/ipv4/tcp_rmem

to reset them to values supported by just about anything.

-- 
     2. That which causes joy or happiness.