mctr fails to accept all HC connections
If a large number of HC try to connect to the mctr, some of them are rejected.
Steps and/or TTCN-3 code to reproduce
Try to start ~ 30 HCs at the same time.
What is the current bug behavior?
Some HCs can't connect, because the TCP connection is refused
What is the expected correct behavior?
All HC connects
When the mctr opens the listening port, it sets the backlog to 10. When a new connection is accepted, a possible time consuming reverse DNS query is executed. If the number of the waiting connection exceeds 10, the new attempts are rejected by the kernel.
simply increase the backlog. The current value remained unchanged since the beginning.
"If the backlog argument is greater than the value in /proc/sys/net/core/somaxconn, then it is silently capped to that value. Since Linux 5.4, the default in this file is 4096; in earlier kernels, the default value is 128."
So it is safe to increase it to 4096
Platform details (OS type and version)