We have deployed Network Load Balancer target to nginx webserver using PHP-FPM.

We are receiving various reset count shown in below image. Could any one help understanding these counts?

CodePudding user response：

These are TCP RST packet counts. For a TCP connection to remain alive, either party should exchange some data before idle timeout. On a UNIX OS (server/target), idle timeout is governed either by tcp_keepalive_time or tcp_keepidle parameter. On the client it depends upon how it's implemented or it may use the same parameters if it's also a UNIX OS. If either of the parties fail to send any data, the connection is closed after which if a client or a server send anything they'll receive a TCP packet with RST bit set and they'll know that the connection is no longer valid.

• Client Reset Count: The total number of reset (RST) packets sent from a client to a target

• Target Reset Count: The total number of reset (RST) packets sent from a target to a client

• Load balancer Reset Count: The total number of reset (RST) packets generated by the load balancer. It usually happens in cases where any target has started to fail or is being marked unhealthy or for a connection request to a target which is already marked unhealthy.