Avoiding Conflict in the Ephemeral Port Range

Article ID: CVD0002 Avoiding Conflict in the Ephemeral Port Range


Avoiding Conflict in the Ephemeral Port Range


Ephemeral ports are temporary ports used for communication that are assigned from a designated range of ports for this purpose. Each operating system defines an empheral port range for dynamic use by the operating system and applications.  For example; Microsoft Windows uses a large range (49152-65535) by default. Other operating systems may use a larger or smaller range of ports. Communications requiring use of a dynamic port will draw that port from the ephemeral range.

Commvault software uses Ephemeral (or Dynamic) ports for scaling of data management and transfer connections between components. 

Some applications may require use of a specific ephemeral port.  For example; By default, Commvautl software requires ports 8400, 8401 and 8402. However, these port numbers can be changed if necessary.


Some applications may require specific ephemeral ports which can't be changed. This may cause conflict if Commvault software dynamically acquired and is using the same port. Normally when a connection terminates, the ephemeral port is released for reuse, but most IP stacks won't reuse the port number until the entire pool of ephermal ports has been used. If the application specifically requires that port number, it may be prevented from establishing communication.

To avoid conflict with other application port requirements the empheral port range for an operating system can be changed. We recommend using the range 49152-65535.

See the following link on how to determine/change the ephemeral port range for each operating system.