DusMac

It seems like the latest version of ICS solved the problem. Tested with 2000 clients disconnecting / reconnecting many times, now working like a charm. Nevertheless I implemented watchdog in case service stops listening, but didn't manage to trigger it. Anyway, thanks for the tips

Using TCPView and netstat revealed that service doesn't even listen to this port anymore. It seems I will have to implement some kind of watchdog to see if server is active at all

OK, some news - linger is disabled, no change - client error is "ConnectionRefusedError : the connection was refused by the peer (or timeout) - netstat shows no TCP connections to port used by service

Thanks for the answers, linger option was enabled, let me try with this first. OS is Windows Server 2019 Datacenter Edition.

Have specific service, having to handle 2000+ connections while processing large amonuts of data. Data is processed in separate thread using FIFO buffer. The problems appear when many TCP clients disconnect / reconnect in short time. When repeated few times service shows no client connections, but clients are unable to reconnect until service restart. Using TSslWSocketServer with TSslContext (TLS 1.2 encryption). In memory I am keeping track of each socket/context with timestamp of last data received, if idle for more than 60 seconds socket gets disconnected/closed. In normal conditions there should be some data at least every 5s from every client. Any idea what am I doing wrong ?