I suggest using http://www.google.com/linux and put in the following search terms:
<name of distro you are using> <networking you need help with; lan, dhcp,etc> Howto .
The mailing lists will have solutions for you.
In addition, the BSD flavors have sections on user quotas.
http://www.google.com/bsd
Currently i have the trouble with the traffic between the LAN with LAN. When i have the LAN A connect to LAN B with the vpn through the ISP SDSL technologies, In between, some of the users have downloading or uploading the files. so it might have a big files. When another users trying to access to the another side, it may becomes times out or slow respond back.
So I'm thinking of how can to control the speed limitation of each users without any costs. The server might using the Unix or Linux depending.
Any idea will greatly appreciated.
Thanks

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