Network Routers

Certain network router operating systems can be configured to send regular HTTP(S) requests to Tom Knows Tech Health Checks directly from the router. This is a handy way to monitor them: when the router loses its WAN connection, it will not be able to ping Tom Knows Tech Health Checks, and Tom Knows Tech Health Checks will notify you about the outage.

DD-WRT

DD-WRT is a Linux-based firmware for routers that runs on wide variety of router models. DD-WRT ships with a cron daemon and wget utility. You can enable the cron daemon and edit crontab in DD-WRT control panel, Administration › Management › Cron.

The crontab syntax on DD-WRT is:

[cron expression] [username] [command]

Example for sending a ping every minute:

* * * * * root wget https://healthchecks.tomknows.tech/ping/your-uuid-here

Screenshot:

MikroTik RouterOS

MikroTik RouterOS is a router operating system used primarily on MikroTik network hardware. Among its many features is scripting support and a scheduler.

First, create a script in WebFig, System › Scripts › Add New. Use the following parameters:

• Name: ping (example, you can use a different name)
• Policy: read, test
• Source: /tool fetch url="https://healthchecks.tomknows.tech/ping/your-uuid-here" output=none

Then, create a schedule in WebFig, System › Scheduler › Add New. Use parameters:

• Interval: 00:01:00 (one minute)
• Policy: read, test
• On Event: ping (the name of the script from the previous step)

Notes:

• The output=none parameter tells the system to discard response body. Without this parameter, the system will save response body to a file, which will additionally require the write policy.
• The "tool fetch" utility supports HTTPS URLs but does not verify TLS certificates by default. You can add check-certificate=yes parameter to require a valid TLS certificate. Note that RouterOS ships with no root CA certificates, so you will also need to load these.
• Here's the full list of options supported by "tool fetch".