Ping HostMonitor - FAQ

How is the “ping (tcp)” test performed?

This is the basic test to verify the host is reachable. It sends a TCP/ECHO, and wants a reply in the form of ether a SYN|ACK or RST. I.e. there is NO need to install an echo server to monitor a host, but you do need to have connectivity on port 7/TCP. Most often this will work without any actions, but if you are in a firewalled environment this may be an issue. E.g. the firewall may reply with a RST for a closed port, interpreted by HostMonitor as the target is up. In this case, you have to use another test method (e.g. http).

How is the “ping (udp)” test performed?

This test is not as reliable as the tcp ping, but in some cases the tcp ping does not work at all. This test sends an udp datagram to port 33500 (i.e. the traceroute range) and expect an icmp port unreachable (“any reply”) back.

Why no icmp ping?

The Android operating system only allows system applications (root) to use icmp.

Why does the test sequence of a host stop at the first failed test?

This is to avoid the cockpit syndrome. If you don’t have network connection to a host, and “ping” fails, there is of little use to also alert you that services like http fails as well. Make sure you order your test sequence in a sound order, e.g. ping before http etc.

Can I disable monitoring of a host?

Yes, set “Reachable via” to “No network” to temporary disable monitoring of that host.

Can I disable all monitoring of all hosts?

Yes, in settings, set “Poll interval” to “Manually” and no testing will be performed unless you manually open the app. Each time you wake up the app, one single test of all hosts will be performed, but no tests are performed in the background.

It doesn’t work on my telephone!

Contact us with a bug report and we’ll fix it in the next release. If you don’t report it, it is very likely not going to get fixed.

I would like to see all my monitored IP as separate line items.

If the host got multiple IP addressees, you’ll get this by defining one host entry per IP address, instead of using the domain name.

I’d like an audio alarm instead of a notification.

You can assign each host an unique signal to play when it becomes unreachable. Click on the loudspeaker at the host configuration page to choose.

I get false alarms!

Increase the test timeout in the settings menu. This will increase the timeout as well as the number of retries, decreasing the risk of false alarms.


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