From HostThyself

The function of the SSH server is to allow encrypted remote connection to the server.

OpenSSH is a popular SSH server

Other SSH servers include

[edit] Troubleshooting

Error:

Generating SSH1 RSA host key:                              [FAILED]

Solution:

mknod -m 0644 /dev/random c 1 8
mknod -m 0644 /dev/urandom c 1 9