No, sorry, NUM is only available for Windows.

NUM is compatible with any version of Windows from XP up to 10, including Windows Server.

A NUM license allows registering the program on one computer at a time. You can unregister a license on one computer and then reuse that license key to register NUM on another. Registering the program removes the trial time limit.

You can purchase multiple licenses to register any number of computers at lower prices, as shown on our Purchase page.

If several computers share the same internet connection, you only need NUM on one of those computers to monitor connection failures.  If you want to test connections in different locations, such as home and office, you need at least one license for each.

Your registered NUM license is connected to the computer you are using it on.  You can “unregister” the license and then register it again on a different computer.

To unregister your license, click License Info on the main form.  On the License Info form, click Print This Form to print a hard copy of your license key.  Then click Unregister License.  That makes the license key available for reuse.  The NUM program will switch back to Trial mode.

On your new computer, download the current version of NUM from this web site and install it, then register NUM with the same license key.

That’s the default setup when you install NUM, but you can turn it off and on in the Settings.

NUM generates a very small amount of data traffic. If you run NUM 8 hours a day with the default settings, you will download about 250 megabytes of data in 30 days. Upload is much less – under 10 megabytes in 30 days.

No. NUM consumes very little resources: Task Manager reports the process uses 0% of CPU time and 11 megabytes of RAM.   On a 4 gigabyte computer, that’s less than 3/10th of one percent of the RAM.

No. That’s a very different kind of test. To test speed, you have to have a server available that will send you a data file of a good size and at the highest speed your connection might possibly handle. That server also has to be fairly close by to prevent slow down from sending the data across many connections.   Net Uptime Monitor has users around the world, so that would mean servers everywhere! is a free service that maintains just such a worldwide network of servers to perform that kind of speed test. Visit the web site to test your connection speed.

Yes. Some connections, particularly satellite or dial up, can take longer than the default limit of 200 milliseconds (2/10th of a second) to respond, causing NUM to report a failure. A NUM user in Afghanistan reported that the normal response time for Google is a full second!

If your connection is very slow to respond, just click the “Change Settings” button and increase the setting for “Wait for Ping Response”.   A good way to determine the best setting is to put it at the maximum of 1500 (1.5 seconds) and then watch NUM for a while and note the range of typical response times for each server. Change the Ping Response time setting to about 1.5 times the highest normal response and NUM should give you reliable reports of actual failures.

That’s normal and it’s not a connection failure.  The test just takes an instant and there is only one test every five seconds.  If a test fails, the light turns red and NUM goes on to the next test immediately.  The red light stays on, but that just means that one server didn’t respond  to that one request. Ten seconds go by before NUM tries that one again and the light turns green.

Your connection actually is working. What’s probably not working is your Domain Name Service, or DNS.

Computers on the internet, whether it’s a server at Google or your PC at home, are actually identified by a number – like for Google. That’s called an IP (Internet Protocol) address. The DNS is the phone book of the internet. Your browser needs the IP address of the server you want to get that web page from, but you just have to type in the name – Your browser sends that web site name to the DNS server and DNS sends back the IP address you need. That has to happen before your browser can ask the web site’s server for the actual page.

In most cases, your computer is set to use a DNS service provided by your Internet Service Provider. These ISP DNS services can be slow or occasionally even unavailable.

Using a different DNS service could be more reliable and also faster – reducing the delay you see before a requested web page begins to load. There are free public DNS services you can use including Google’s DNS or OpenDNS. The specifics of how to change your DNS can be found on the OpenDNS web site at   To use Google’s DNS, follow the same directions but use the IP addresses and

Even when your DNS is down, Net Uptime Monitor keeps reporting that it’s connecting because NUM does not use names to specify server addresses; it uses the numerical IP address directly. This means it doesn’t need or use the DNS.   That’s a key feature of NUM’s design – it tests the connection, not your DNS service.

Yes, just click the “Change Settings” button, then the “Change Target Servers” button. Detailed instructions are in the Help file.

The three default servers are extremely high reliability, public, and free. OpenDNS provides services to over 50 million users every time one of those users enters a web site address in their browser. Level 3 is one of only six main providers (Tier 1 networks) of the internet backbone in the United States and around the world. And Google is – well, it’s Google.

The purpose of NUM is to test whether your internet provider is connecting you to the whole of the internet and using these servers tells you if they are doing that job!

Monitoring your router as one of the three Ping targets won’t really tell you anything.  If your router isn’t responding, then nothing is going to get through and all three servers are going to fail to respond.  The same thing would happen if you just left the three default servers. NUM can tell you when your internet connection fails but there’s no way it can distinguish between a failure at the router, at the cable from your house to the curb, at the big cable from the curb to your ISP, etc., etc.   NUM will tell you when your connection is down but it can’t tell you why – that’s for you and your ISP to work out.

Generally, one of the first things your ISP will tell you to do is to connect your computer directly to their modem and not through a router – this eliminates the router as a possible source of the problem.   Use NUM while the router is out of the connection path to prove to your ISP that your router is not the issue.

No, that requires different programming, and we don’t offer that capability at this time

No.  All programs are “suspended” when your computer is in a power saving state.  NUM will be running when the computer wakes up, but network failures while the computer is sleeping will not be detected or logged.

If you want NUM to test around the clock, change your “power and sleep” settings to prevent your computer from sleeping.