Oracle Database Discussions

Hello,

I just  installed Oracle on mu Ubuntu 12.4 following the instructions provided here:

http://www.makina-corpus.org/blog/howto-install-oracle-11g-ubuntu-linux-1204-precise-pangolin-64bits

and here:

Install Oracle Database 11gR2 on Ubuntu 12.04

However, when I try to log on to the database I've created during install using sqlplus, it hangs for a minute or two until it errors out with:

ORA-12170: TNS:Connect timeout occurred.

My tnsnames.ora:

MYSID =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = my_host)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = mySID)
    )
  )

I verified that the listener is running and listening at the post 1521:

s$ sudo netstat -tulpn|grep 1521

tcp6       0      0 :::1521                 :::*                    LISTEN      16732/tnslsnr 

$ ps -ef|grep 16732

oracle   16732     1  0 06:58 ?        00:00:00 /opt/oracle/product/11.2.0/dbhome_1/bin/tnslsnr LISTENER -inherit

Thoughts?