Connecting to Oracle DB with LDAP-Credentials So I would like to connect to a remote Oracle database from my Linux system using the oraclient 19c on the command line, but whenever I try to connect it sees the realmpart of my username as the server. 

For example I want to connect with my username "USER@REALM.DOMAIN" to the database identified by "DB" in my tnsnames.ora, i do sqlplus USER@REALM.DOMAIN@DB and of course it complains with ORA-12154: TNS:could not resolve the connect identifier specified, because it thinks "REALM.DOMAIN" is the database. 

When I try it without the realmpart like sqlplus USER@DB it returns ORA-01017: invalid username/password; logon denied.

How can I pass my username to the client?
For special usernames, use double quotes.

SQL&gt; create user "USER@REALM.DOMAIN" identified by 1;

User created.

SQL&gt; grant create session to "USER@REALM.DOMAIN";

Grant succeeded.

SQL&gt; connect USER@REALM.DOMAIN/1
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified


Warning: You are no longer connected to ORACLE.
SQL&gt; connect "USER@REALM.DOMAIN"/1
Connected.
SQL&gt;