Enable SSH on Fedora 15

"Secure Shell or SSH is a network protocol that allows data to be exchanged using a secure channel between two networked devices. The two major versions of the protocol are referred to as SSH1 or SSH-1 and SSH2 or SSH-2. Used primarily on Linux and Unix based systems to access shell accounts, SSH was designed as a replacement for Telnet and other insecure remote shells, which send information, notably passwords, in plaintext, rendering them susceptible to packet analysis. The encryption used by SSH is intended to provide confidentiality and integrity of data over an unsecured network, such as the Internet."

--wikipedia

Enable SSH Daemon
Open gnome-terminal and type:

$ su
# systemctl start sshd.service

Now that it's started you'll need to keep it going in case you reboot your machine. Run the following command to have it start on-boot:

# systemctl enable sshd.service

After executing that command you will receive a message below:

sshd.service is not a native service, redirecting to /sbin/chkconfig.
Executing /sbin/chkconfig sshd on

Verify Firewall Setting
Check the port 22 is open in the firewall.

Test the Connection
I test the ssh on my Windows machine with SecureCRT. In SecureCRT, add a new connection and input your ip, user name and password in corresponding places.

The first time when you connect the ssh, you need to accept a host key.

After all are done, enjoy it!