DDNS Connection

[fotingo]

I notice every time my ISP modem reboots for any reason, the DDNS on my Asus router becomes "inactive".

Even if I click on Apply again at the bottom of the screen, it won't connect. I've tried disabling and re-enabling the service, still does not connect.

But, if I enter a new Host Name and register it, then it becomes active.

At that point I can enter my regular Host Name and hit Apply, and it stays active.

Is this a normal behavior, or do I need to make a change on a setting for the service to reconnect after the Internet is back?

Thank you.

 

[fotingo]

I have been looking and found Dynu which provides free ddns server. I set up an account with them and was able to get "Registration Successful" on the router after entering my login from Dynu.
But, I realized I used Dyndns.org as I thought it was Dynu.

My question is, if Dynu and Dyndns are not the same company, how come I was able to use the same credentials and get a successful registration?
I also used the same credentials with namecheap.com and also got a "Registration Successful".

Is this normal?
How come I am able to use the same credentials for dynu, dyndns and namecheap?