Global Listener and X Servers

The global listener and the X servers are the communication servers of the SAP MaxDB database system. They are located on the database computer. Applications (via interfaces) and tools need them to connect to databases that are located on remote database computers.

Note Note

The JDBC interface requires an X server even for local communication. Therefore all tools and applications that use the JDBC interface to connect to a database also need an X server for local communication, for example Database Studio.

End of the note.

There is one X server acting as a global listener on each database computer, and one X server for each SAP MaxDB installation. This means that on each database computer, there are at least one global listener and one X server.

Note Note

For the communication between older clients and databases as of version 7.8 as well as for communication between clients as of version 7.8 and older databases, the global listener acts as X server (downward-compatibility). Only for communication between clients and databases that are both of version ≥ 7.8, the global listener additionally provides the port-mapping function as described below.

End of the note.

To connect to a remote database, you have the following options:

You specify the database name, the port number for the database and the database computer.
You are then directly connected to the X server of the installation to which the database belongs, and this X server connects you to the database.
You only specify the database name and the database computer. Internally, the system executes the following steps:
1. The global listener receives the connection request and sends back the port number of the database.
2. You are then directly connected to the X server of the installation to which the database belongs, and this X server connects you to the database.

Ports and Protocols of the SAP MaxDB X Servers
Scope	Default Port	Function of the X Server	Protocol	Protocol Identifier
All installations on the database computer	7210	Global listener	TCP/IP	`remote://`
	7269	Global listener with SAP networtk protocol NI (for connections via SAPRouter, only available in SAP systems)	NI (based on TCP/IP)	`sapni://`
	7270	Global listener with SAP networtk protocol NI and SAP encryption library (for connections via SAPRouter, only available in SAP systems)	SSL/TLS NISSL (based on TCP/IP)	`remotes://` `sapnis://`
First installation `<installation_1>` on the database computer	7200	X server for `<installation_1>`	TCP/IP	`remote://`
Second installation `<installation_2>` on the database computer	7203	X server for `<installation_2>`	TCP/IP	`remote://`
Separate Database Studio installation	7299	X server for the separate Database Studio installation, only used by the system to access the local user management database `.UMDB`	TCP/IP	`remote://`

Connections to the database via SAPRouter are always established via the global listener. These connections use the NI or the NISSL protocol with designated ports.

For more information, see Concepts of the Database System, Network Communication.

SAP MaxDB Global Listener and Installation-Specific X Servers: Processes and Services
	Process Name (Microsoft Windows)	Service Name (Microsoft Windows)	Process Name (Unix/Linux)
Global listener	`serv.exe`	`XServer`	`globallistener`
Installation-specific X server at`<port>`	`serv.exe`	`XServer-<port>`	`vserver`
NI server (for connections with SAPRouter, in SAP systems only)	- (part of the global listener)	-	`niserver`
NISSL server (for SSL connections with SAPRouter, in SAP systems only)	- (part of the global listener)	-	`nisslserver`

Communication between clients on remote computers and the X server can be encrypted with SSL/TLS in SAP systems.

For more information, see Database Administration, Encryption.

Features

More Information

SAP MaxDB Security Guide, Accessing SAP MaxDB Databases Behind a Firewall