Route traffic to multiple POPs around the world
Lower latency, high-available redundancy, etc.
Method 1: Geo DNS
- Unique IP address per region
- Approachable solution for most customers
Method 2: Anycast IP
- Same IP address for all regions
- Requires a /24 (IPv4) and/or /48 (IPv6) address block.
- Mainly used by larger networks and key infrastructure: cloud providers, registrars, DNS server constellations, root servers, CDNs, etc.
List of Geo DNS Providers
List of Anycast IP Providers
Domain Apex Limitation for GeoDNS
- For optimal routing, always use a CNAME sub-domain (e.g.
www.example.com) that points to
commons.host. Never use a domain apex (e.g.
example.com) to point at the CDN.
- Avoid using non-standard hacks like ANAME (Constellix), ALIAS (NS1), or CNAME flattening (Cloudflare).
- DNS providers do not seem to consider EDNS information when resolving ANAME/ALIAS/flattened CNAME records.
- Single region per DNS provider PoP. E.g. if Constellix only has a SEA PoP in SG then it will never return the closest PoPs for the MY, VN, or ID regions to users based there.
GeoDNS PoP Naming Scheme
$COUNTRY is the 2-letter country code defined by ISO 3166-1 alpha-2.
$INDEX is an integer, starting from 1, incremented by 1 for each new PoP in the same city.