PDA

View Full Version : Cannot access some websites in FC6?


riverotter
2007-03-08, 06:43 AM CST
I found out recently that some websites are inaccessible to those using Windows Vista and Fedora Core 6.

For example http://robgarrett.com/cs/ is not accessible or very slow to some people using routers in Fedora Core 6 or Windows Vista (not in IE7 though). (at the moment - this website may change)

The problem is TCP windows scaling (or autotuning).

There are two options: You can turn off windows scaling in FC6 or can make server-side changes.

SERVER-SIDE

On the websites I was working on, the solution was eventually found in updating the firmware for a server firewall:

The "resolved issue" in the release notes is this :

45187: Symptom: The SonicOS management UI has display problems due to dropped traffic that is dependent on the RFC 1323 TCP Window Scale Option. Condition: Occurs when the SonicOS management UI is running on a system with Microsoft Windows Vista, which uses the Window Scale option to negotiate a larger window than permitted in RFC 793.

FEDORA CORE 6

If you want to access a website but don't have access to the server (most probable), this worked for me. Please note that although it worked, there may be some unpleasant consequences which I don't know about - do post here any other preferred solutions to this problem.

Open up a terminal (Applications --> Accessories --> Terminal)
Write: "su", then put your password in.
This will get you into admin mode
Write:

gedit /etc/rc.local

This will open up gedit. At the bottom of the gedit file (it will probably be quite empty) copy and paste the following:

echo 256960 > /proc/sys/net/core/rmem_default
echo 256960 > /proc/sys/net/core/rmem_max
echo 256960 > /proc/sys/net/core/wmem_default
echo 256960 > /proc/sys/net/core/wmem_max

echo 0 > /proc/sys/net/ipv4/tcp_timestamps
echo 1 > /proc/sys/net/ipv4/tcp_sack
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling

Save the file and close. Close the terminal. Restart computer.

If the website http://robgarrett.com/cs/ didn't work before, it will do now. (I have nothing to do with this website, but this website highlighted the problem in Vista)