DBA_DB_LINKS

All database links in the database

Columns
   ___________________________
 
   OWNER
      --
   DB_LINK
      Name of the database link
   USERNAME
      Name of user to log on as
   HOST
      SQL*Net string for connect
   CREATED
      Creation time of the database link

Related:

DBA_2PC_NEIGHBORS
DBA_2PC_PENDING
DBA_PENDING_TRANSACTIONS