To enable your business to work online properly can look like the end of a complex process, but it’s actually only the beginning. Once online, you will have to frequently adjust, modify, add, delete information, DNS records, etc. Changes will be required to adapt to new conditions, compete strongly, grow, expand, etc.
In this context, DNS propagation will be a process you will have to get involved with.
DNS propagation definition.
DNS (Domain Name System) propagation is the process of updating and fully spreading such DNS update across your network.
Every modification or addition you make on your DNS, no matter if it’s strategic or part of the regular maintenance, will be saved only in the authoritative DNS nameserver. But that’s not enough for the modifications to be available for all users. The DNS chain involves different DNS recursive servers strategically located around the world. They play a very important role in the necessary DNS resolution process for your website to be reached by users. All these servers require to be up to date for working properly.
Consider that DNS recursive servers have a cache memory to store the last update of your DNS records. This copy will last there until DNS records’ TTL (time-to-live) expires. If in the meantime, you modify something, it won’t automatically propagate to all servers. So the old copy will be used by recursive servers until they receive the new update. This means until the DNS propagation process gets completed (updating of every server on the network).
The time to fully propagate data and changes can be lower or higher. To give you a concrete time reference, it can take up to 72 hours. But it’s a reference, not a rule.
DNS propagation will be needed every time you modify TTL values on your DNS records, route the e-mail, redirect users to subdomains, add, remove or edit DNS records, etc.
What can affect the DNS propagation process?
Different factors can affect the DNS propagation process.
- TTL of DNS records. Servers are configured to store DNS records for a defined time. Until this period expires, they search for an update (propagated changes).
- DNS modifications in the highest hierarchy level. DNS servers obey a hierarchic structure. When modifications are made on the root servers, DNS propagation takes longer because TTL values at that level usually are established to last longer (two or more days) to avoid stress caused by hard use.
- TTLs from ISP’s servers. Internet service providers (ISP) supply you with the Internet service, but they have their own way to configure their DNS. Usually, they configure higher TTL values on their servers to make the DNS traffic more agile and optimize their resources. ISPs also cache domains’ DNS records to serve faster queries of the same domain. Therefore, your DNS changes could be propagated until the TTLs of the ISP servers expire.
- DNS cache on users’ devices. Users’ devices also cache DNS records of the domains they visit. They remain on the memory until the TTL expires. It can happen that even you already made modifications, users’ devices still try to use an old IP address. Either the DNS cache is deleted or wait until the TTL expires for the new update to propagate.
DNS propagation is an essential process you will regularly face while administrating your DNS. You can influence it in your favor by manipulating TTL values here and there. But to master this, you need to understand perfectly the details of the process.