Editor’s note: The following review is part of Macworld’s GemFest 2012 series. Every weekday from mid June through mid August, the Macworld staff will use the Mac Gems blog to briefly cover a favorite free or low-cost program. Visit the Mac Gems homepage for a list of past Mac Gems.

NetUse Traffic Monitor uses Simple Network Management Protocol (SNMP) to acquire network traffic information, usually from the router that delivers Internet data to your wired and wireless devices. Many modern consumer-grade wireless and wired routers (including Apple’s Airport Extreme, AirPort Express, and Time Capsule) support SNMP. Be sure that your router supports SNMP, and that SNMP is enabled in your settings. (DewDrop Studios provides a free utility, SNMP Test, which you can use to verify your router’s compatibility.)

When you launch NetUse Traffic Monitor for the first time, the app tries to locate and connect to an SNMP-compatible router. If there’s a problem with SNMP access, you may face some troubleshooting here.

The online and in-app help offered could use improvement—do you know your router’s gateway address, or the SNMP community-string password NetUse Traffic Manager needs to get started? A thorough walkthrough of problems and solutions would be a big help for network configuration novices.

Once NetUse Traffic Monitor has found your router, it will begin tracking upload and download traffic between your network and the Internet. (You can set it to exclude uploads if you wish.) The usage graph displays traffic in real-time—hourly, daily, weekly, monthly, and annually. Keep it running at all times to maintain a complete record.

Below the graph, a segmented bar shows upload and download traffic, and estimates monthly data transfer based on past usage. If you know that your Internet account comes with a 10GB per month bandwidth cap, and that your billing period begins mid-month, configure NetUse Traffic Manager to alert you when you’ve reached a certain percentage of the total.

If your home or business account comes with a bandwidth limit, NetUse Traffic Monitor makes it easy to keep track. The hardest part about using the app is getting it set up: troubleshooting SNMP could be frustrating for some users.

[Shelly Brisbin is producer and host of the App Store Pundit Podcast.]

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