Posted by If you are relying on database links in your application, think carefully about how you want to manage the accounts that you connect with, in particular, when it comes to password expiry.
With a standard connect request to the database, if your password is going to expire soon, you will get some feedback on this:
SQL> conn demo/demo@np12
ERROR:
ORA-28002: the password will expire within 6 days
Connected.
But when using those same credentials via a database link, you will not get any warning, so when that password expires…you might be dead in the water.
SQL> create database link demolink connect to demo identified by demo using 'np12';
Database link created.
SQL> select * from tab@demolink;
TNAME
------------------------------------------------------------------------------------------------
TABTYPE CLUSTERID
------- ----------
EMPLOYEES
TABLE
Learning is not a spectator sport 
Used to be easy. Until “security” maniacs stopped us from resetting the passwords for db links by eliminating the BY VALUES option.
But heck, who wants to make life of a dba easy?
Certainly not Oracle, of late…
😦