SSHDaemon Class

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The SSHDaemon class is used to create Secure Shell (SSH) servers. The class handles multiple simultaneous connections on the same TCP/IP port (service port). It is designed to balance the load between connections for a fast, powerful server.

Syntax

class ipworksssh.SSHDaemon

Remarks

The SSHDaemon class is the SSH-enabled equivalent of the IPWorks IPDaemon class, extended by a set of new properties and events that deal with SSH security. The ssh_compression_algorithms and ssh_encryption_algorithms properties determine which protocols are enabled for the SSH handshake. The ssh_cert* properties are used to select a certificate for the server (please note that a valid certificate MUST be selected before the server can function). The on_ssh_user_auth_request event will allow you to use authenticate clients using digital certificates or passwords. Finally, the on_ssh_status event provides information about the SSH handshake and underlying protocol notifications.

By default, each instance of SSHDaemon can handle up to 1000 simultaneous incoming connections (this number may be increased up to 100,000, or decreased to a lower value by using the MaxConnections configuration setting).

SSH connections are identified by a ConnectionId. Events relating to these connections as a whole will use the ConnectionId to identify the specific connection. Connections may also contained one or more multiplexed channels, which are identified by a ChannelId. Channel-level events will specify the ChannelId to which they relate.

SSHDaemon can start to listen on a port by setting the listening property to True. When a remote host asks for a connection, the on_connection_request event is fired. At that point, the connection can either be accepted or rejected. If the connection is accepted, a ConnectionId is assigned, and communication can start. From this point on, the operation is very similar to SSHClient. Data can be sent to an individual SSHChannel using send_channel_data. The address and port of the incoming connection can be found by querying the client_remote_host and client_remote_port properties.

Note: Server components are designed to process events as they occur. To ensure events are processed in a timely manner do_events should be called in a loop after the server is started.