I use a client socket connection to monitor my solar panels. After moving IP-Symcon from a Windows 10 client to a fresh installed Windows Server 2019 system it is no longer possible to make a connection with my SolarEdge SE17K invertor.
A few seconds after activating the client socket connection the “Waiting for connect timed out.” appears.
This connection has worked without any problem on Windows 10. Other Client Socket connections with Raspberry Pi’s are working fine on Windows Server.
IP-Symcon V5,0, kernel date 16-12-2018
Windows Server 2019, latest updates
The Windows firewall is off. I get replies on the ping command.
IP-Symcon logfile
02/04/19 20:35:38 | 22852 | ERROR | Event Control | Reconnecting [SolarEdge Modbus new] failed = Waiting for connect timed out
Windows Application eventlog, Source: PHP-7.2.9
PHP Warning: PHP Startup: Unable to load dynamic library ‚php_pdo_oci.dll‘
C:\IP-Symcon\ext\php_php_pdo_oci.dll.dll (The specified module could not be found.)) (C:\IP-Symcon\ips.exe)
Today I tested IP-Symcon 5.1 on Windows Server 2019, the communication problem still exists.
I used Wireshark to compare the communication between the SolarEdge inverter and IP-Symcon on Windows 10 and Windows Server 2019.
The intial packet sent after Activating the socket in IP-Symcon differs.
Windows 10 initiates the communication with the Flag [SYN], SolarEdge answers with [SYN ACK]
Windows Server 2019 initiates the communication with flags [SYN, ECN, CWR], SolarEdge answers with [RST]
Why does Windows Server uses the flags ECN and CWR?