root@TTS-ubuntu:/var# ssh -vvv $USER@localhost
OpenSSH_5.5p1 Debian-4ubuntu6, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to localhost [::1] port 22.
debug1: connect to address ::1 port 22: Connection refused
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: connect to address 127.0.0.1 port 22: Connection refused
ssh: connect to host localhost port 22: Connection refused
root@TTS-ubuntu:/var# grep -i listen /etc/ssh/sshd_config
# What ports, IPs and protocols we listen for
#ListenAddress ::
#ListenAddress 0.0.0.0
root@TTS-ubuntu:/var# su ttsadmin
ttsadmin@TTS-ubuntu:/var$ ssh localhost
ssh: connect to host localhost port 22: Connection refused
ttsadmin@TTS-ubuntu:/var$ ssh ttsadmin@localhost
ssh: connect to host localhost port 22: Connection refused