Also I can do
CREATE DATABASE LINK "DBLINK_TEST" CONNECT TO databaseB IDENTIFIED BY <PWD> USING '(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST =abcd.com )(PORT = 1521)) ) (CONNECT_DATA = (SID = xyz) ) )';
So I assume network configurations are in place.
SQL> conn db1/password1@databaseA Connected. SQL> conn db2/password2@databaseB Connected. SQL> conn db1/password1@databaseA Connected
Do I need to open firewall between S1 and S2 for the dblink to work. As of now they are not opened.
ORA-12170: TNS:Connect timeout occurred
From forums and other sources and you say, I MIGHT need to open firewall. I am really trying to understand here, does it imply we can make dblink work between servers without opening firewall. Like I need a confirmation saying without firewall opened, IT IS IMPOSSIBLE for dblinks to work.
Yes you might need to open the firewall.
That is a way of testing if firewall is opened. Firewall is not opened
telnet other_system 12345
Yes it does.
I take it that this enty actually uses the remote Oracle username rather than what you posted.