I have spent all day looking for clues as to how to debug network
performance issues without success. Nobody seems to answered my
previous post on this subject - so I thought I would try again.
The problem I have is this. I have a linux desktop (machine D) siting
on a LAN in my home. This is connected to a linux firewall/nat router
(machine S) with two ethernet cards. One links out to the internet,
the other connects to the internal lan. Connections to the internet
from machine D go through machine S, which acts as a NAT translation. I
do all the control and firewalling using IPTABLES in machine S.
Downloading a video from youtube onto Machine D's desktop I get a
download speed of about 7Kbytes/sec. Which is very low. If I try to
download the same one by ssh'ing into mahcine S and running wget on the
same url, I get a download speed of 80Kbytes/sec (ie more than 10 times
faster).
This would normally imply a bottle neck in the network between machines
D and S. But if I download a similar file from machine S to machine D,
then I get a throughput of about 11Mbytes/sec.
I have do idea about how to debug this and find out what the problem is.
Can someone here give me some clues as to what to do.
--
Alan Chandler
http://www.chandlerfamily.org.uk