The expanses of WolfWings' land
scratched on the wall for all to see


December 10th, 2006
December 10th, 2006
December 10th, 2006
December 10th, 2006
December 10th, 2006

[User Picture]10:39 pm - Yum!

Just made some couscous, forgot how trivial it is to make, and how fun it can be to have. =^.^= Boil a cup of water with a little olive oil in it (debatable if it takes longer in the microwave or on the stove... so little water just heats up instantly) then dump it in a cup of couscous in a bowl, swirl the bowl, set the pot on top of the bowl for a couple minutes, eat with a fork.

On a side-note... I've determined what makes some pages and images flat-out stall when loading them.

In laymans terms, if you have a LOT of RAM (say over 256MB) and run a recent version of Linux, you'll have some servers that magically stall when loading images from, for example. Reloading will cause more of the image to load usually, etc, etc.

The core problem is that newer versions of Linux don't limit the upper size they'll use for TCP buffers to a static value from the days of computers having 4MB of memory. It limits the value based on 1/128th of your usable system memory now, up to 4MB. This is in the internet standards, and has been for 12 years. So what breaks it? Most firewalls don't track the entire TCP connection, and the part often dropped is the part that negotiates the total size of the buffers to be allowed to use. In laymans terms... the firewall expects box #1 to be filled, but the two computers told each other to use boxes #1-#16. So the firewall never checks boxes #2-#16 for data to pass along to the other two computers... and the other two computers keep waiting to hear about mail in boxes #2-#16 to be able to assemble the network traffic properly.

For the geeks: The technical term is TCP Window Scaling, and it happens when a firewall tries to track SYN packets statelessly while still tracking TCP connections statefully. To disable it under Linux, add the following to /etc/sysctl.conf:


net.ipv4.tcp_window_scaling = 0


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