Hi,
I'm still seeing slow performance with my port-forwarding but have found something interesting that may be problematic.
Just to re-cap:
I have one Linux 66.283.12.21 box and one Windows box 192.168.0.10
I can download a file of the linux box at around 140K/s
That very same file download on the Windows machine is around 15K/s using DNAT and Masq/Forwarding.
However we can upload to the Windows box at 140k/s.
So it is only slow, 15K/s, when the data is coming from Windows then through the Linux Iptables Masq/Forwarding Firewall.
I contacted an earlier Admin for the Windows machine and was informed the TCP window size has been manually increased.
Could this affect Forwarding in Iptables ?
The default maximum TCP window size in Win2000 is 17520 bytes (12 segments).
The current value is set at 131400.
90% of the traffic being port-forwarded are Digital video files. These range in size from 2MB to 200MB.
So I assume with large files like these Windows would opt for it's largest TCP window size.
I guess the next step is to lower these to their default values and see if it affect bandwidth.
Your thoughts on that would be much appreciated.
Thanks. Regards, Rudi
Your increased windows size should not affect the network performance. Windows machine performance - maybe, but not network overall. The tcp window is like a bucket representation. When your host is flooded with packets, it will send back syn/ack packets with win 0, which will make the source host retransmit the data again later until window > 1.
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