Dave Plowman wrote:

Andy Burns wrote:

Can every PC ping every other PC regardless of what they're connected
to, by IP addr? by name?

No. Only when they are are all cabled or on the same Wi-Fi

Worth double-chking that all PCs allow ICMP echo requests through their
local firewall, eitheit from a command line or the firewall GUI

https://www.howtogeek.com/howto/windows-vista/allow-pings-icmp-echo-request-through-your-windows-vista-firewall/