SAP J2EE Engine 6.20 Telnet Service enables remote administration using a distributed, scalable Telnet server that supports remote Shell administration using Telnet clients. This service supports most types of Telnet clients.
A remote connection can be established if the remote machine (in the LAN) has an installed and running SAP J2EE Engine 6.20, and the local machine has a Telnet client, through which connection to the server can be established. To connect to SAP J2EE Engine 6.20 using Telnet, complete the following steps.
To establish a successful connection, the administrator must set the Telnet Service port on which SAP J2EE Engine 6.20 nodes listen for connections to Telnet clients. The default value is 2323. It can be viewed or modified either using the dispatcher part of Telnet Service in the Visual Administrator, or using the property file located in <SAPj2eeEngine_install_dir>/cluster/dispatcher/services/telnet/propertie.
The administrator must run a Telnet client and connect to the target machine by setting the host and the corresponding port (for example, hostname:2323 ). If connection is established, a “Welcome” message is displayed.
The administrator must be authenticated to SAP J2EE Engine 6.20 to perform remote administration. Enter valid login info, including user name and password (for example, for user name “Administrator,” and for password “”). If the input information is incorrect, the link is disconnected and you must restart the Telnet client.
When the Telnet client is connected to SAP J2EE Engine 6.20, a prompt for Shell commands execution is opened. This enables administration of both dispatcher and server nodes – that is, separate command prompts are not available for each cluster element.
By default, the Telnet Shell is opened on dispatcher element, and the Shell commands that are executed on dispatcher are available. By using the
LSC
command, you can display all server components with ID, component name, host, port, and type. The first displayed component is the current one. To pass from one component to another, use the
JUMP
command and specify the ID of the target node (for example, executing
jump 4001
enables remote administration of a cluster element with ID 4001). This command is available for Telnet administration only. All Shell commands for dispatcher or server administration are available too. To close the connection, type
exit
on the command line.
Note: For more information about Shell commands, refer to the Shell Commands Reference section in the Administration Manual.
The cluster is accessed remotely using a dispatcher. The
JUMP
command redirects the terminal to an application cluster element (a server). The initial login enables only restricted permissions. You can use the
LOGIN
command available on server cluster elements to obtain authorized access to the server resources. However, no security is applied to the dispatcher cluster elements. Therefore, an anonymous user could use the
SHUTDOWN
command on a dispatcher to stop the server using Telnet.
A security resource called
system.telnet
serves manages access restrictions when using Telnet. Only users granted access to this resource (actions/instance are not applicable to the resource) are permitted to connect to the cluster using Telnet. By default, all users can use Telnet. Access restrictions can be changed using the interfaces of the security resource context (Visual Administrator or Shell commands).
On Telnet startup the service initializes the
system.telnet
resource (if not initialized already) with access granted to
root
user group – that is, all users can connect using Telnet.