by the way i got confused, in this place it's RB750, not RB2011 - i doubt that makes any diff though.i manually created no-ip_ddns_and put 188.8.131.52 in it. in the file it says i thought maybe i should manually put 184.108.40.206 in there and see how it works.
Authentication is done using HTTP Basic authentication - if it fails, the standard HTTP 401 'Unauthorized' response is given.
The update is done using a very simple HTTP request to the fi server URI /nic/update.
Currently we only support pointing a hostname to the IP address of the HTTP client.
People sometimes call those sub-domains, but I think it is more helpful to understand that these are just different host names, a host is a computer and the domain name is like a top level name for a group of computers.
The structure is basically hostname.domainname, so in the case of is the host name portion and is the domain name portion and when they are put together that is a fully qualified host name, ie the host name is qualified by the domain name.
When you purchase a domain name like mydomain.com, that is a host name, but it is considered the default host name for the domain because it has no host segment.