Add port exclusions from dynamic port range

Adding a recommendation to exclude one port when SQL Server engine, SQL Listener, or Health probe port is using one port that belongs to the dynamic port range for TCP/IP. 
This will prevent any system task of taking this port, sometimes when SQL Listener or health probe is using ports from this pool can be taken in one SECONDARY replica and this could prevent complete the failover process to this replica.

Author: DBAlberto

articles/azure-sql/virtual-machines/windows/performance-guidelines-best-practices-checklist.md

@@ -154,7 +154,8 @@ For your SQL Server availability group or failover cluster instance, consider th
    - Use a unique DNN port in the connection string when connecting to the DNN listener for an availability group. 
 - Use a database mirroring connection string for a basic availability group to bypass the need for a load balancer or DNN. 
 - Validate the sector size of your VHDs before deploying your high availability solution to avoid having misaligned I/Os. See [KB3009974](https://support.microsoft.com/topic/kb3009974-fix-slow-synchronization-when-disks-have-different-sector-sizes-for-primary-and-secondary-replica-log-files-in-sql-server-ag-and-logshipping-environments-ed181bf3-ce80-b6d0-f268-34135711043c) to learn more. 
-
+- If SQL Server Database engine, SQL Listener, or Health probe port is configured to use a port from the Default dynamic port range for TCP/IP (https://docs.microsoft.com/en-us/windows/client-management/troubleshoot-tcpip-port-exhaust#default-dynamic-port-range-for-tcpip) between 49,152 and 65,536, it is recommended to add one exclusion for each port, this will prevent any system process taking this port, here an example: 
+netsh int ipv4 add excludedportrange tcp startport=59999 numberofports=1 store=persistent
 
 To learn more, see the comprehensive [HADR best practices](hadr-cluster-best-practices.md).