When your routers don't have a fix IP address and the dynamic IP address changes every day, then it makes sense to use a DNS name because you cannot change the configuration of the Instreamer / Exstreamer every day. DNS translates a unique name to a IP address. On the Internet there are some DNS registration services, DYNDNS.org is a very popular DNS service and supported by many routers.
Before you can use a DYNDNS – DNS name you have to create a account on www.dyndns.org, and select/register your DNS name. The account and the registration of a DNS name on DYNDNS is free of charge. The name should be a little more specific than 'myhome' and must be unique in the whole world. Once you have created your account and registered a valid DNS name then you have to configure your router so that the router updates the DYNDNS server every time when the router gets a new IP address from the ISP. Check first which services are supported on your router.