Looking for a working example of sshd_config setup fille

[Robert Heller]

At Mon, 18 Aug 2025 15:26:18 +0100 "Ubuntu user technical support,? not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:

> 
> On 18/08/2025 14:43, Colin Law wrote:
> > Ah, so when you said
> > 
> > "The default is that you cannot ssh or scp INTO another system on
> > the same network (same OS)."
> > 
> > What you meant was "The default is that you cannot ssh or scp INTO 
> > another system on the same network running an old version of the
> > same OS which has an insecure configuration of ssh server."
> No, I meant exactly what I wrote. Both systems were running the latest 
> version, installed from the same USB stick ISO. Nothing to do with old 
> versions of anything, as far as I know (which may not be very far).

Are either machine running some sort of local firewall?

Are you certain that sshd is enabled and running on the target machine(s)?
Default port (22) or some other port? What does "sudo systemctl status sshd"
tell you?

> 
> > I think that is a good thing as connecting to an insecure system
> > could potentially compromise your machine.
> My concern is what might happen if an external agent penetrated my 
> Internet provider's connection from the world outside.

What ports (if any) are open on your router?  Ideally, there should be NO open 
ports on the WAN side of your router.  If no ports are open on your router's 
firewall and if your WiFi is properly secured, then it is unlikely that an 
external agent penetrated your systems.

> 
> Peter
> 

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