I presume you got an error message of the form Exiting subroutine via goto. Which is what you are trying to do, and isn't allowed.

I don't think you need the goto - I would check the return value of the eval, and exit if the eval succeeded. Or rather, only execute the second ping if the first failed. Something like this (untested):

#
# Generalize to multiple ips
#
my @ips = ("192.168.0.0", "google.com");
$SIG{INT} = sub {
    print "Caught SIGINT: $?\n";
    die if $?;
};
foreach my $ip (@ips) {
    print $ip, "\n";
    last if eval {`ping $ip`; 1};
}
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Note that I do not wrap the eval in a pointless do construct, I'm not needing a flag variable, and I'm not storing the output of ping in a variable that I'm not going to use.