On Unix based system (Linux, Solaris ..), only super user (root) can start any process on port <= 1024 . From security reasons its is not desirable to run WebLogic server as root user. Solution is to start WebLogic process as root (bind on port 80, 443) and then switch process to non privileged user like oraweblogic or nobody.
This is done by setting four properties in WebLogic -
weblogic.system.enableSetUID (Set User ID)
weblogic.system.enableSetGID (Set Group ID)
weblogic.system.nonPrivUser(Non privledged user)
weblogic.system.nonPrivGroup(Non privledged Group)
1. By setting value of enableSetUID to true; you are instructing weblogic server to switch from ROOT(after starting weblogic server on port 80, 443 or <=1024) to lower privileged user.
2. Value assigned to nonPrivUser will be used to own weblogic server process, once its been started by superuser in port <= 1024
3. Ensure that lower privileged user should have proper access (read, write or both depending on type of type) on files (log, classes..) required by weblogic server.
4. If you wish to start and access weblogic server on both SSL (443) and non SSL (80); you need to define two Listen Port.