monit 'if failed port' not working

[Matei C.]

Hello,

I am running Armbian Xenial 5.60 on a Rock64 single board computer, which is based on Ubuntu 16.04.

I have noticed that monit (xenial,now 1:5.16-2 arm64) does not detect when a port is closed on this particular setup.

For example, I have the below entry in my "monitrc" config file;

  check host MYHOST with address 192.168.1.12
    if failed port 4444 then alert

And although port 4444 is actually closed , monit does not view it closed... here's an extract of the debug log when starting monit as "monit -Iv"

  Socket test failed for [192.168.1.12]:4444 -- Connection refused
   'TEST' succeeded testing protocol [DEFAULT] at [192.168.1.12]:4444 [TCP/IP] [response time 0.701 ms]
   'TEST' connection succeeded to [192.168.1.12]:4444 [TCP/IP]

If I use a non existent IP to test, it seems to work and fail at the ping test, yet it cannot tell if a port is closed and always marks it as open.

* OS release:

  Description: Ubuntu 16.04.5 LTS
  Release: 16.04

* monit version

$ sudo apt show monit
Package: monit
Version: 1:5.16-2ubuntu0.2
Priority: extra
Section: universe/admin
Origin: Ubuntu
Maintainer: Ubuntu Developers <email address hidden>
Original-Maintainer: Sergey B Kirpichev <email address hidden>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 777 kB
Depends: libc6 (>= 2.17), libpam0g (>= 0.99.7.1), libssl1.0.0 (>= 1.0.2~beta3), lsb-base (>= 3.2-13)

Please let me know if more info is needed.

P.S.

I have another monit (5.20.0) running on a Raspian 9.6 which detects failed ports with no issues, so I believe this should work in monit 5.16 as well.

Thanks!