[Discuss] Do Cheap NAT Routers "Fill up"?

[kentborg at borg.org (Kent Borg)]

A little Python is a dangerous thing...

I was running a script that does a lot of http GETs to a remote machine 
with a fast network connection (linode), and after awhile it slows down, 
and I notice other things on my computer also slow down, things like a 
DNS lookup of google.com.

I wrote an even simpler Python script that does a single packet ping of 
8.8.8.8 and then does a dig of a list of well known names (things like 
google.com, yahoo.com, ...) and it like to run fast at first but then 
slow down, with some really long pauses.

This the simpler over DSL. So I plugged in my phone and did a tether 
through it. It behaves similarly. I tried running the simpler script on 
a Linux on a different DSL network across the country and it worked 
better there, but still seemed to deteriorate.

Then I tried running it on my linode machine and it ran fine there.

The difference is the NAT? In each case where I am behind a NAT it 
starts fast and then slows down. On the one case where I had no NAT it 
ran fast. Do cheap NAT boxes not know how long to keep their records, 
and get plugged up?

Thanks,

-kb