Why Some Regions Update Faster Than Others During DNS Propagation

One of the most puzzling aspects of DNS propagation for many users is the unevenness of how quickly changes are reflected across different parts of the world. After making an update to a DNS record—whether it’s pointing a domain to a new server, modifying mail exchange records, or changing name servers—people often find that the new configuration appears in some regions within minutes while other areas take hours or even days to catch up. This inconsistent behavior can be both frustrating and difficult to diagnose, but it is rooted in the technical structure and operational diversity of the global DNS infrastructure. Understanding why some regions update faster than others requires a deep dive into caching behaviors, ISP policies, DNS resolver configurations, and even the geographical distribution of internet traffic.

At the heart of this discrepancy lies the fact that DNS resolution depends heavily on caching. Every time a DNS record is resolved, it is stored—or cached—by the resolver that handled the query. This cache persists for the duration defined by the TTL (Time to Live) value associated with the record. Until that TTL expires, subsequent queries to the same resolver will return the cached result, regardless of whether the authoritative DNS server now holds updated information. This fundamental caching behavior is efficient but introduces latency when changes are made to DNS records. The crucial detail, however, is that the way caching is handled varies significantly depending on which DNS resolver is involved, and resolvers are typically managed by ISPs or third-party DNS providers that may be regionally distinct.

ISPs and DNS service providers in different regions operate their own recursive DNS resolvers, and these resolvers do not share cache data. A DNS record cached by an ISP in Germany, for example, has no impact on the cached data held by a resolver in Brazil or Australia. Each resolver will independently cache the record upon its first query, and until that cache expires, it will continue serving that version of the record to its users. This means that users in a region whose ISPs happen to query a domain after a change was made will get the updated data immediately, while users in regions where the record was cached just before the update will be served outdated information until the TTL expires.

The policies ISPs use for caching can also vary widely. Some follow TTL values strictly, refreshing records as soon as the TTL dictates. Others override short TTLs with longer minimum values to reduce the frequency of DNS lookups and lower operational load on their infrastructure. This behavior is especially common among smaller or budget ISPs, which may prioritize network efficiency over strict compliance with TTL settings. In practice, this means that even if a domain owner sets a low TTL—say, 300 seconds—to enable faster propagation, some resolvers around the world might still cache the record for an hour, twelve hours, or even longer. Regions served predominantly by such ISPs will, as a result, appear slower to update.

Geography also plays an indirect role through the design of DNS resolver networks and how users are routed to them. Large, global DNS providers like Google Public DNS or Cloudflare operate resolvers in data centers all over the world using anycast routing. Anycast allows a user’s query to be routed to the closest available server in terms of network topology, not just geographic proximity. However, network conditions, peering agreements, and interconnectivity between ISPs can all influence how quickly a user’s query reaches a resolver with a fresh cache. In some cases, queries from two users in the same country might be routed to entirely different resolver nodes in separate regions or even continents, resulting in different responses to the same DNS question depending on where the cache is fresher.

Latency and network congestion also factor into the equation. In regions where infrastructure is slower or more heavily congested, DNS queries may experience delays in reaching authoritative name servers, which affects how often resolvers decide to refresh cached data. Additionally, in some areas of the world, ISPs rely on upstream DNS providers or hierarchical resolver chains to handle requests, adding yet another layer of caching that must be cleared before updated DNS information is retrieved. These extra layers of caching can further extend the delay between a DNS update and its visibility in certain locations.

Moreover, some regions have more proactive DNS resolver strategies. Advanced resolvers may preemptively refresh their cache in anticipation of TTL expiration, especially if a domain is queried frequently. This can result in faster update times for popular domains in regions with advanced resolver infrastructure. Conversely, less frequently queried domains in regions with fewer optimizations may take longer to update, even if the domain’s authoritative records have changed and TTLs have expired.

In summary, the speed at which DNS changes propagate across different regions is shaped by a complex web of caching mechanisms, resolver policies, network infrastructure, and routing behavior. ISPs in each region implement their own DNS strategies, which can either accelerate or delay the recognition of updated DNS records. Larger, better-connected networks tend to update faster due to more frequent cache refreshes and optimized resolver configurations, while smaller or isolated networks may hold onto outdated records much longer. As a result, global DNS propagation is inherently asynchronous, and the varying speeds across regions are not only normal but inevitable given the decentralized and distributed nature of the internet’s DNS system.

One of the most puzzling aspects of DNS propagation for many users is the unevenness of how quickly changes are reflected across different parts of the world. After making an update to a DNS record—whether it’s pointing a domain to a new server, modifying mail exchange records, or changing name servers—people often find that the…