between branch office's lan and router [connecting to outher world] i plan
to "insert" controling workstation with two nics, and instal some software
to monitor traffic, make logs and also take care of established quotas
[bandwith] for every user [represented by their nic mac] and also to deny
forbiden connections.

may i have some advice is it reliable to make [such managing ws] and what
software tool to employ?