ffap-machine-p

ffap-machine-p is a compiled Lisp function in `ffap.el'.

(ffap-machine-p HOST &optional SERVICE QUIET STRATEGY)

Decide whether HOST is the name of a real, reachable machine.
Depending on the domain (none, known, or unknown), follow the strategy
named by the variable `ffap-machine-p-local', `ffap-machine-p-known',
or `ffap-machine-p-unknown'. Pinging uses `open-network-stream'.
Optional SERVICE specifies the port used (default "discard").
Optional QUIET flag suppresses the "Pinging..." message.
Optional STRATEGY overrides the three variables above.
Returned values:
t means that HOST answered.
'accept means the relevant variable told us to accept.
"mesg" means HOST exists, but does not respond for some reason.