What is the ip of my host?

So, you have two routers? In that case, if you wish to run an update client on the router, you must only configure the one directly connected to the Internet to update your hostname.

Just in case you don't mean to have two routers in one network:
The Update Client must and can work only out of the network, which you call "the remote router where is a dvr". If you run it on the local network, i.e. from where you access the DVR as client, it will catch this IP address and wrongly update your hostname for your remote network with the local (client) network's IP address. The reason is: an Update Client can get the WAN IP address only from its own network, where it is running. There is no other way.

Or much more clear: You cannot get a remote dynamic IP address from remote, only from within the related network of this IP address.

Your router (Asus N13) apparently doesn't do its job very well. Presuming that this is the one running in the same network as your DVR. Is there a router log revealing more details?