There are many different types of possible data paths. It is recommended that your port configuration stay within the realm of default protocol Request For Comment (RFC). However, your LoadMaster may be configured to use whichever port happens to be most appropriate for your particular network. For more information regarding port definitions, refer to Microsoft documentation at https://docs.microsoft.com/en-us/exchange/network-ports-for-clients-and-mail-flow-in-exchange-2013-exchange-2013-help.