Please add a feature in check_by_ssh to skip the host_or_die() check.
I have host aliases defined in my system ssh_config (/etc/ssh/ssh_config) that are only accessible via ProxyCommand. There are no DNS records for those systems since they exist outside the local network, and are not accessible except through a Proxy.
case 'H': /* host */
hostname = optarg;
If I comment out the `host_or_die()` and re-compile check_by_ssh seems to work perfectly fine to connect to the systems I have defined with aliases in my ssh_config.