INET: Source port perturbation table size (as power of 2)

configname: CONFIG_INET_TABLE_PERTURB_ORDER

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>INET: Source port perturbation table size (as power of 2)
In linux kernel since version 4.9.3 (release Date: 2017-01-12)  
Source port perturbation table size (as power of 2) for
RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm.

The default is almost always what you want.
Only change this if you know what you are doing.