What is DNS dynamic update?
Dynamic DNS updating involves changing the IP address associated with a DNS record. The changes happen automatically, in real time, and are not noticed by the user.
Previously, this kind of change may have been done manually, but by using an update client, updates can now be lightweight, fast, and behind the scenes. The host computers are able to receive an address from a DHCP server or through automatic configuration, then notify the DNS server. DNS updates can be configured through the server, allowing DDNS client computers to update their resource records whenever the changes happen. It’s also possible to disable this feature if it’s not needed or if it’s causing security issues.
What is dynamic DNS used for?
Dynamic DNS is used for IP address management, often for residential or small business customers, or for any business for whom a static IP address is not an option. It is also useful for Active Directory functions, remote and changing device location, and remote access.
For instance, when workstations join a domain, Active Directory uses DDNS to create DNS entries so hosts can track these devices. AD can track when IP addresses and host names join and leave the network, and update DNS records as needed. Clients enrolled in Active Directory can dynamically update their DNS records when the IP address changes, while AD ensures that inactive records are removed.
Additionally, dynamic DNS is useful for organizations with devices that may move to various locations and even connect to other networks. With DDNS, it’s possible to maintain device IP address updates despite these changes. Similarly, dynamic DNS allows for remote control functionality. If you need to access a device that has a changing IP address like a home device or small business security camera, you can utilize the fixed domain name. This may require software that takes dynamic DNS updates into account.
Dynamic DNS and DHCP
Typically, DDNS means the client device gets its IP settings from a dynamic host configuration protocol (DHCP) server. DHCP is a network protocol that allows the server to automatically assign an IP address—whether static or dynamic—to a computer. When a user turns on a computer with a DHCP client, the broadcast request goes to the DHCP server, which then assigns the appropriate address. For homes or small businesses, the router acts as the DHCP server.
DHCP makes it easy to automatically add devices, so it’s useful for larger networks, especially since the alternative to using DHCP is to manually assign an address to every device. While the DHCP server can distribute static addresses, with dynamic IP address assignment, the chances are lower that two devices will use the same IP address.
Once the DHCP server has assigned an IP address, it can communicate this to a DNS server, which then updates that information. Or, the client itself can transmit the information to the DNS server. It’s important to note that dynamic IP addresses are not appropriate for devices that need ongoing access like printers or file servers. Offices should not use DHCP for these devices, as that would require workstations to constantly reconfigure their connections.
As an MSP, you may be called on to configure dynamic DNS for your customers or set up a DHCP server.
Read through our blog for other common questions and concerns with DNS.