Download the binary, make a Caddyfile
myservice.example.com {
basic_auth {
admin some_password_hash_here
}
reverse_proxy :3000
}
And then just "./caddy start"domain1.com -> service on port 1234
domain2.com -> service on port 5678
domain3.com -> serving a file directory.
And then you still access domain1.com, domain2.com, domain3.com on port 80/443