Why does NUM show a failed connection when my internet is working?

You can use your web browser and get email, while NUM is displaying a failure to connect. There are several reasons why this could happen.


1.  Slow response times

NUM works by sending a “ping” request to the target servers. The servers respond and NUM knows your connection is working. NUM waits a specified length of time to receive that response before it considers it to have failed, then it tests the next server. If all three servers fail to respond, NUM knows that your connection is down.

The default “Wait for Ping Response” time for NUM is 200 ms (milliseconds or 1000ths of a second). A typical broadband connection shows response times in the 20-40 ms range for the default test servers. The 200 ms default wait time allows plenty of margin for the response.

If your connection regularly has much slower responses, then NUM may show a connection failure even though you can still use the web or your email. Possible reasons your response times may be longer include satellite or DSL connections as opposed to cable or fiber. A remote location can have slow response – one NUM user in Afghanistan reports constant 1000 ms response times.

To allow NUM to accurately detect connection status when you have longer response times, just go to the Settings and change the “Wait for Ping Response” time to the maximum of 2000 milliseconds. Then observe the NUM display for a while to see what your typical response times actually are. Finally, set the “Wait for Ping Response” time to approximately 1.5 times your typical ping response time.


2.  Security software or router is blocking NUM

One of the ways security software protects you is to prevent any unknown program from accessing the internet. For example, a virus or other malware might try to send data it finds on your computer back to the villain who created the problem software. Programs such as Norton or MacAfee have this kind of “firewall” function.

This software might not recognize NUM as having a legitimate purpose in using your internet connection. If it blocks NUM from accessing the internet, then NUM is going to report a connection failure while your other programs are communicating without a problem.

The security software may ask you if it’s OK for NUM to access your connection. That makes it easy to grant permission and solve the problem. If the security program blocks NUM without asking, you’ll need to find the setting in the security program that lets you add the NUM program (NetUptimeMonitor.exe) to the list of approved software that uses the internet.

Google “(your security software name) allow program to use internet” to find instructions on changing those settings.

It’s also possible that your router is set to block the Ping requests NUM sends, also known as ICMP ( Internet Control Message Protocol) requests.  Google “(your router manufacturer / model) enable icmp”.


3.  The connection’s bandwidth is full.

You can use your computer in all the normal ways and NUM will also continue to work normally. However, there are some uses of your computer that are designed to use 100% of the available bandwidth in your internet connection. This can delay any response from the requests NUM sends from arriving in a timely way, causing NUM to report a failure.

Two particular applications that can cause your bandwidth to be completely filled are Speedtest.net and Bit Torrent.

Speedtest, the web site that tells you the speed of your connection, naturally has to fill your connection completely to determine the maximum capacity. That will cause NUM to report a failure.

Bit Torrent is a system that allows your computer to download a file from many sources simultaneously, most commonly used for distributed sharing of large files. There are a lot of programs that use the Bit Torrent protocol and they can also use your entire bandwidth.