EC2 instance region via IP Address

Question

I'm trying to get my EC2 instances to communicate better with APIs of a 3rd party service. Latency is extremely important as voice communication is heavily involved & lag is intolerable.

I know a few of the providers use EC2, but the thing is Amazon's IP system makes it difficult to find which region the instance is in. With non elastic-ip services I could do a whois and find if it was in Australia or somewhere in Europe so I could put a server close by.

With these elastic IP's how can I find which zone they're in. I can use ping times but its a bit of a guess and I have to make all these instances in different regions to find the shortest ping time.

Answer 1

Amazon EC2 regularly publishes its Amazon EC2 Public IP Ranges , which clusters them by Region.

• It does not cluster them by Availability Zone (AZ) (if you actually meant that literally), but this shouldn't matter much, insofar cross AZ latency should regularly be within single digit milliseconds range only.

Other than that you might also be interested in my answer to How could I determine which AWS location is best for serving customers from a particular region? , which outlines two other options for handling this based on external data/algorithms or via the Multi-Region Latency Based Routing now Available for AWS (which would likely only be useful when fully embracing Amazon Route 53 as well).

Answer 2

Put your server behind a Route 53 DNS and let Latency Based Routing do the rest for you - it can decide automatically for you the least latent server.

http://aws.typepad.com/aws/2012/03/latency-based-multi-region-routing-now-available-for-aws.html