Anyone familiar with the workings of DNS?

I really need some help with this dns stuff if anyone knows all about domain forwarding.

---

[www.mediafire.com] Some say you should click it, you know you want to. [www.gp4central.com] <----GP4 Central

This is a large portion of my day job, as it happens. Maybe I can help?

---

I registered a domain name, to use it to view an ip camera. (example) mydomain.com. This domain is registered on freedns.afraid.org which is not really free as I have to pay for domain registration.
It has a sub-domain which re-directs to my ip and port. (example) test.mydomain.com:81
The top domain cannot have a port added to the ip, as it returns an invalid ip address in the configuration, so the sub-domain which allows a port in the configuration has to be used.
I use a dns updater as I have a dynamic ip, if I had a static ip I would not need a domain as I could just use the static ip and port as it would never change. However, as my ip is dynamic and does change I need to use a domain which can have my ip updated by an updating script tool. The updater works fine.
So, why is it that my top domain returns nothing when tested but the sub-domain works fine and takes me to my camera log in page?

---

[www.mediafire.com] Some say you should click it, you know you want to. [www.gp4central.com] <----GP4 Central



Edited 1 time(s). Last edit at 09/25/2013 11:21PM by mortal.

It's likely that the root domain and sub-domain are pointing in different ways - your root record is likely to be of type 'A', which can only point to a specific IP address, whereas your sub-domain will likely be a CNAME record, which can point at your dynamic DNS address. If you want, you could PM me your domain name and I can double-check this for you.

---