A software implementation that enables SSH access to a system from SSH clients. SSH server may be included with an operating system or appliance or may be add-on software. An SSH server is typically a complex set of software modules responsible for a broad number of tasks, including enforcing configured SSH settings, authenticating users, limiting access to certain users and groups, ensuring secure connections, interfacing with other systems (e.g., PAM and Kerberos), performing file transfers, etc.
Source(s):
NISTIR 7966