The ISP determines if it has the IP address associated with that name; If not, the ISP forwards the request to other providers in an effort to located the DNS record that contains the data. Once the record is found, the IP address of the domain is returned to the user. Now, the user's computer can communicate directly with the server.

With Dynamic DNS you can easily run a mail or web server on a home broadband connection even though your IP address may change periodically. Simply install one of the many dynamic DNS clients on your server, or configure any router with a built-in dynamic DNS module and you're good to go. The DNS makes using TCP/IP-based applications much more friendly, by routing users to specific network locations by name rather than by number. Dynamic DNS, DDNS or DynDNS is a method of automatically updating a DNS server in real time when a devices IP address changes. DynDNS can circumvent the need for a dedicated or static IP address. Dynamic DNS (DynDNS), found under Services > Dynamic DNS, will update an external provider with the current public IP address on the firewall. This keeps a constant DNS hostname, even if the IP address changes periodically. Whenever an interface changes in some way, DHCP lease renew, PPPoE logout/login, etc, the IP will be updated. The dynamic domain name address was supplied by DHCP server of your ADSL service company. #2. The working theory of DDNS. On the DNS server, the domain name has to point a static IP address. Most of residential users don't have a static IP, the IP is changed periodically. Hence, it's impossible to use the DNS server for dynamic IP addresses.

Jun 25, 2018

Currently Hikvision supports two paid DDNS services: DynDNS and NO-IP. Technically both work the same way, however this article shows the steps for the DynDNS only. Some routers offer free DDNS, it’s a good idea to check your router settings to see whether there’s a free DDNS service there. How To Easily Access Your Home Network From Anywhere With Jul 03, 2017 Supported Third Party DDNS Services

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There are billions of IP addresses currently in use, and most machines have a human-readable name as well.; DNS servers (cumulatively) are processing billions of requests across the internet at any given time. Millions of people are adding and changing domain names and IP addresses each day. Free and Public DNS Server List (Valid July 2020)