Reserve ports to prevent portmap mapping them
The portreserve program aims to help services with well-known ports that lie in the bindresvport() range (currently 600-1023).. It prevents programs requesting a port to the libc from occupying a real service's port by occupying it itself, until the real service tells it to release the port (generally in the init script).
acquired package info from repodata DB: repodata/f1f85c23079e7764ad00378a9fc5d660b89a03657290e75426caf7be5b7da462-primary.sqlite.bz2
Man pages and other related help documents for portreserve.