5 ms·

I wonder if this is related to connection tracking?

• john37386 8y ago
  By default, Amazon uses stateless firewall. It means that by default it's not tracking connections.
  • spydum 8y ago
    I think you may be mistaken. Security Groups are stateful: https://docs.aws.amazon.com/vpc/latest/userguide/VPC_SecurityGroups.html https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Securit... As suggested, it's very likely they hit the connection tracking limitation: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-network-security.html#security-group-connection-tracking https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-ne... I've personally witnessed teams hit this specifically for DNS (usually for internal, where you have explicitly permitted src/dst).
    • john37386 8y ago
      Yep I mistaken Security groups with Network Acl. Thanks. It's in the best practices to not track dns for big systems. From powerdns https://doc.powerdns.com/recursor/performance.html https://doc.powerdns.com/recursor/performance.html
    • gstaro 8y ago
      Thx for the clarification. Had the same misconception