With regards to Database Links, I can look at dba_db_links to see what that particular instance's DB Links to other instances. Is there a way to tell which other instances have DB links to the instance that I'm currently in? Maybe entries in the data dictionaries?

For example,
Instance A has a DB_Link -> Instance C & Instance D. I can find these in DBA_DB_LINKS when logged in to Instance A.

However, Instance B has a DB Link -> Instance A. Is there a way to tell, logged in to Instance A, that Instance B has a db link to Instance A?

Thanks,
Paul

select sid, serial#, username, program
from   v$session
where  program like 'oracle@%';