4 ms·

We are seeing sporadic connection issues where tcp syn packets are dropped before reaching our elb. Have noticed off and on for a few weeks now. Still investiga

• toast0 6y ago
  Do ELBs operate behind the 'security groups' firewall? I don't think they do, but if they do, you might be hitting connection tracking limits? It's consistent with dropped syns. Some more details below, but if you use normalish (naive?) rules in the aws firewall, you get connection tracking behavior and there's an unspecified connection limit for each instance type. Above that limit, incoming syns are dropped. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-security-groups.html#security-group-connection-tracking https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-secu...