Ports are a logical point of connection provided and managed at OS level. OS directs the data arrived at NIC for a specific port to its specified application. SQL Server ports are used at instance level and a port can not be shared among multiple instances on same machine. Before going in to detail of ports configuration for SQL Server level, we should have a look at categories of ports
IANA Reserved Ports
These ports range from 0 to 1023. The Internet Assigned Numbers Authority (IANA) allots these ports only to standard protocols. Vendors or users may not use any port within this range.
Vendor Reserved Ports
Ranges from 1024 to 49151. These ports are registered by IANA for applications of specific vendors. Other users are not able to use any port within this range. For SQL Server the default reserved port in 1433.
Open for Users Ports
Ranges from 49152 to 65535. Ports within this range may be used for end user purposes. If we want to use dynamic or static customized port number then it should fall in this range.
SQL Server Default Port
Port Types in SQL Server
- Dynamic Port (fall in the range between 49152 to 65535)
- Static Port
- Default Port (1433)
- User Allotted (Any port between 49152 to 65535)
Choosing Between Static and Dynamic Port
Can we use more than one port for single instance?
Here is a very good post about the ports that a DBA should have essential knowledge of. It contains the ports for all SQL Server endpoints and services.
And also a very good point added by Yusuf Anis
“And for those who still have pre win 2k8 boxes with them the dynamic port range is limited to 1024-5000 on both TCP & UDP.”