Override External IP: The external IP is usually configured automatically during connection.However, in situations where the unit is within a private network behind a firewall or router, the network's external IP address will have to be manually configured in this field.Switching to “Static” enables you to set specific DNS servers in the Primary DNS and Secondary DNS fields.Primary DNS and Secondary DNS: If you choose to specify your DNS servers, then enter the IP addresses of the servers you want as your primary and secondary DNS servers in these fields.The DNS server settings will be pre-populated with public DNS server IP addresses.You can override the IP address with any other DNS server IP address of your choice.
Since the assigned name is mapped to an IP address, the device’s IP address should not change.The major disadvantage of this method is that only you will be able to work on your website in the new location, other users might still see and use your website working from the old server.NOTE: make sure to remove the entries added to 'hosts' file 48 hours later when the nameservers are fully propagated. How to check if DNS propagation has completed for you? Due to DNS caches of different levels, after the nameservers change, some of your visitors might still be directed to your old server for some time, whereas others can see the website from the new server shortly after the change. When you open your domain in a web browser, your request is not going to the hosting server directly, it has to pass through several ISP nodes first. When you update the nameservers for a domain, it may take up to 24-72 hours for the change to take effect. In other words, it is a period of time ISP (Internet service provider) nodes across the world take to update their caches with the new DNS information of your domain. Let’s imagine you live in Bari, Italy, and you just have changed the nameservers for your domain that is hosted in Phoenix, USA.
From there, the request goes to the upstream provider in Rome, Italy, then connects to the ISP in Hamburg, Germany.