my $sock = IO::Socket::IP->new(
   PeerHost => $domain,
   PeerPort => $peerport,
   Type     => SOCK_STREAM,
) or die "Cannot construct socket - $IO::Socket::errstr";

my $familyname = ( $sock->sockdomain == PF_INET6 ) ? "IPv6" :
                 ( $sock->sockdomain == PF_INET  ) ? "IPv4" :
                                                     "unknown";
printf "Connected to %s via %s\n", $domain, $familyname;