How do I control Internet bandwidth per IP on my LAN?

your bandwidth per IP for each inbound and outbound interface of your network firewall.

For Linux there is the popular Advanced Routing & Traffic Control website, (http://lartc.org/) which contains information on how to implement traffic management on a Linux server. This solution is robust and costs nearly nothing when compared with similar commercial products.

For Windows, I'd advise you to visit www.tucows.com and www.download.com and search their networking sections as you're likely to find a few different programs to suite your need.

Lastly, if your way cool and have a Cisco router, you can use the "rate-limit" command to control the bandwidth consumed by each IP. If you require further information for this, visit Cisco's site ( www.cisco.com) and perform a search.