See All Hidden parameter in oracle

All hidden parameter as 'SYS' user / SQLNET:

SELECT a.ksppinm Param , b.ksppstvl SessionVal , c.ksppstvl InstanceVal, a.ksppdesc Descr 

FROM x$ksppi a , x$ksppcv b , x$ksppsv c WHERE 

a.indx = b.indx AND a.indx = c.indx AND a.ksppin

To see all SQLNET avaiable parameters :

  sqlnet paramters