Network isolation?

[Peter Flynn]

On 05/03/2022 20:37, MR ZenWiz wrote:
> I have a few computers around the house, but for some reason I don't
> see, from one of them I can't connect to any of the others.
> 
> Basic setup:
> - Desktop, wire connection to the router, connects fine with all the
> other wifi machines.
> - Personal laptop - wifi connection that is proven almost fully
> functional - see below.
> - Two other laptops - also on wifi, exhibiting no problems.
> 
> However:
> 
> My laptop cannot ping any of the others on the wifi.  It has no
> trouble pinging google.com, browsing the web and running zoom
> meetings.
> 
>  From my desktop, I can ssh into the laptop and successfully execute
> most commands.  However, even though I am ssh logged-into that laptop
> from the desktop, the laptop cannot even ping the desktop.

Check very carefully the /etc/hosts and the connection settings for eth1 
or whatever is used, and make sure that all the machine really do have 
the same Class C IP address, and that none of the machine is running its 
own DHCP server.

I had a similar problem a while back and traced it to an /etc/hosts that 
I had edited a temporary name into and forgotten to remove, which was 
matching one of the IP addresses assigned by the router's DHCP server.

Peter