ameshkov/ecssupportchecker

A script that checks for the proper ECS support. Made for the DNS-OARC 41 talk.

ECS support checker

This Node.js script queries domain names against a hardcoded list of subnets using the dig command. It checks the consistency of IP addresses across different subnets for the domains that support ECS.

• Inspired by the NextDNS article on ECS.
• Made for my talk on DNS OARC 41.

How to use

• input.txt - a list with ~1000 popular domain names
• node index.js input.txt output.txt - runs the script that tests every domain in the list for the ECS support and also checks if the response does actually depend on the subnet or if it's the same regardless of the ECS.

Result

Here's the what I've got on Aug 29, 2023:

Overall domains analyzed: 998
Domains that support ECS: 497
Domains that support ECS, but results are the same across subnets: 158