Is it possible to remotely force a reboot on Ubuntu 20.04.3?

[Bo Berglund]

On Mon, 21 Feb 2022 15:01:40 -0500 (EST), Robert Heller <heller at deepsoft.com>
wrote:

>At Mon, 21 Feb 2022 20:16:37 +0100 bo.berglund at gmail.com, "Ubuntu user technical support,? not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:
>
>> What I *should* have done is powering the Ubuntu machine off the timer, because
>> then I would be certain that if a lockup happened it would be solved within 24
>> hours...
>
>Power cycling a Ubuntu machine can be pretty rough on the file systems.
>
>You need to find out what is happening with sshd.
>
>Is there a firewall?  Is fail2ban running?
>
>If a firewall is running, check its configuration.  If fail2ban is running, 
>check its configuration.

Since it is a Ubuntu  machine then I assumethat ufw is running.
I believe I had to add a rule for allowing SSH when I set it up.

>Telneting to the machine on port 22, should *immediately* return a banner like 
>this:
>
>sauron% telnet localhost 22
>Trying ::1...
>Connected to localhost.
>Escape character is '^]'.
>SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.5
>^]
>telnet> quit
>Connection closed.

I showed this failing attempt earlier:

$ telnet aspomint 22
Trying 192.168.117.251...
Connected to aspomint.
Escape character is '^]'.
Connection closed by foreign host.

>The fact that instead aspomint connects and then immediately closes the 
>connection suggests that *something* is listening, but not a working instance 
>of sshd. If nothing was listening (eg sshd had simply crashed), then you would 
>have got:
>
>sauron% telnet phone 22
>Trying 192.168.250.40...
>telnet: Unable to connect to remote host: Connection refused
>
>("phone" is a cell phone, not running sshd)
>

I guess this is futile, either the power company will have to "arrange" a power
outage out there or else I have to wait until I get there in March...
200 km round trip.


-- 
Bo Berglund
Developer in Sweden