Routing through Linux server

[colweb]

I have the following situation: Serverall windows clients, a linux (Slackware 12 - kernel 2.6) server and and alcatel speedtouch adsl modem.

The window clients get there ip-address from a dhcp server running on the linux server (range 192.168.1.10 - 192.168.1.200). The windows client where uTorrent is running always get 192.168.1.99. The default gateway is 192.168.1.250 - dns 192.168.1.240 and dhcp server also 192.168.1.240. (eth0 in the linux box has 192.168.1.240 and eth0:0 has 192.168.1.250). The reason to use two addresses on the same nic is because of sendmail. (with one address sendmail didn't work properly).

The linux server has a second nic (eth1) with address 10.0.0.1 and this side is connected to the alcatel modem (which has address 10.0.0.138).

Within the linux server port forwarding is turned on and masquerade is used (iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE).

Within the alcatal modem under napt I put a line to forward incomming connections to 192.168.1.99 on port 41160 (the port used by uTorrent).

In uTorrent I do see downloading and uploading are working, but always at a very slow speed (under 5kb/s). And the network indicator never turns green.

On the same windows client I used BitTorrent and in the alcatel modem forwarden ports 6881-6889 to 192.168.1.99. BitTorrents network indicator also never turns green, but the download and upload rates are much higher (sometimes over 300kb/s download and over 200kb/s upload).

Found the problem. Within the alcatel modem I had to put 192.168.1.99 (the uTorrent windows client) under ip-routing. Speed is a little higher and the network indicator is green.