Geo DNS gives you the ability to provide differing DNS responses back to clients depending on where the client is geographically located.
In other words, you can provide DNS responses by the country querying it.
Example:
Given:
left | right |
---|---|
North American Datacenter | 10.0.1.6 |
European Datacenter | 192.168.17.4 |
And you would like to geographically distribute the traffic based on this hostname:
left | right |
---|---|
www.example.com | North America, South America |
www.example.com | Europe, Asia |
Once activated, queries for www.example.com originating from North America or South America will receive a 192.168.17.4 response, while anything in Europe or Asia will receive 10.0.1.6.
You can also target responses to individual country granularity.
Geo DNS can be enabled for all of the supported RRTypes including A, CNAME, MX, TXT, SRV, NAPTR, and CAA.
Caveat:
Be aware that Geo DNS is not an exact science. GeoDNS will key off the remote IP address of the resolver making the query.
This means it is possible that the actual visitor making the query is using a resolver that is not in the same geographical location as themselves. In such a case, it is possible, and in those cases probable, that the visitor will receive the response that matches the geography of where their resolver is, not necessarily where they are.
Also note that if your resolver supports edns-client-subnet the system will key off of that, which will mitigate the effect noted above.
Also see:
- Geo Targeted URL Forwarding, which will key off of the IP address of the remote client itself, but only works for URL forwarding.