Some companies have a strict security policy to connect with a database. Mostly the acceptance or production databases are accessable trough the specific hosts and ports, but not with your client.
So, if you can connect to such host trough SSH and you are running Linux, the command below could help you:
ssh -L 7100:dbserver:1521 user@host
dbserver => The database server where the shema’s reside.
user => The linux user which has access to the linuxhost.
host => The host which had a firewall rule to connect to the databaseserver.
7100 => Your port on your localhost machine to connect to the database. (user ports => 1024-49151)
1521 => The database server connection port.
Now you could connect your client with the database by using:
dbserver = localhost
port = 7100
Poor Micr$s$ft users
You could use Putty to create a tunnel: