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In this section you will find an overview of all connection parameters that can be used in the saprfc.ini file.The parameters are divided into 3 different categories:

  • General Connection parameters. These can be used with client and server programs.

  • Parameters used in client programs

  • Parameters depending on the connection type you use

General Connection parameters:




If the connection needs to be made through a firewall using a SAPRouter, specify the SAPRouter parameters in the following format: /H/hostname/S/portnumber/H/


Full path and name of third-party security library to use for SNC communication (authentication, encryption and signatures).

Alternatively you can set the environment variable SNC_LIB.


Token/identifier representing the external RFC program.


Token/identifier representing the backend system


Use one of the following values:

1: Digital signature

2: Digital signature and encryption 3: Digital signature, encryption and user authentication

8: Default value defined by backend system

9: Maximum value that the current security product supports


Use one of the following values:

0: off

1: brief

2: verbose

3: full


Partner character size.

The use cases for this parameter are not very frequent.

During the initial handshake the RFC library obtains the correct value from the backend and uses it from then on.

One rare use case is as follows: you know that the backend is Unicode and want to use a non-ISO-Latin-1 user name or password for the initial logon. As the initial handshake is done with ISO-Latin-1, the characters in USERNAME/PASSWD could not be read and logon would be denied. In that case set PCS=2 and the RFC library will use Unicode for the initial handshake.


Similar to PCS above.

Only needed it if you want to connect to a non-Unicode backend using a non-ISO-Latin-1 user name or password.

The RFC library will then use that codepage for the initial handshake, thus preserving the characters in username/password.

A few common values are:

  • 1401: ISO-Latin-2

  • 1500: ISO-Latin-5/Cyrillic

  • 1600: ISO-Latin-3

  • 1610: ISO-Latin-9/Turkish

  • 1700: ISO-Latin-7/Greek

  • 1800: ISO-Latin-8/Hebrew

  • 1900: ISO-Latin-4/Lithuanian/Latvian

  • 8000: Japanese

  • 8300: Traditional Chinese

  • 8400: Simplified Chinese

  • 8500: Korean

  • 8600: Thai

  • 8700: ISO-Latin-6/Arabic


The values can be customized in the backend system. Contact your backend system administrator before modifying these settings.


By default the RFC protocol compresses tables, when they reach a size of 8 KB or more.

In very special situations it may be useful to turn this off, for example if you are transporting very large integer/binary tables with "random" data, where compression would have no effect, while consuming CPU resources.

Parameters used in client programs:




User name




The Client to which to logon.


Logon Language.

Either specify the two-character ISO code (like 'EN' for English, 'KO' for Korean) or the one-character SAP-specific code (like 'E' for English, '3' for Korean).


ISO codes are case-insensitiv, while the SAP codes are not.

For example 'D' logs you on in German, while 'd' logs you on in Serbian, if that language is installed in your system.


Use this parameter instead of USER and PASSWD to log on with an SSO2 ticket (Single-Sign_On).


Set this to 1, if the backend should generate an SSO2 ticket for your user. If RfcOpenConnection() succeeds, you can retrieve the ticket with RfcGetPartnerSSOTicket() and use it for further logons to systems supporting the same user base.


Use this parameter instead of USER and PASSWD, if you want to logon with an X.509 certificate.

The certificate needs to be Base64 encoded and needs to be mapped to a valid user in the backend's user configuration.


Old logon mechanism similar to SSO. No longer recommended.




If you set this to 0, RfcOpenConnection() only opens a network connection but does not perform the logon procedure. I.e. no user session will be created inside the backend system.


This parameter is intended for executing the function module RFC_PING only.


Specifies whether a SAPGUI should be attached to the connection. Some (old) BAPIs need this, because they try to send screen output to the client while executing. Possible values are:

0: no SAPGUI (default)

1: attach a "hidden" SAPGUI, which just receives and ignores the screen output

2: attach a visible SAPGUI.


Note that for values other than 0 a SAPGUI needs to be installed on the machine, where the client program is running. This can be either a Windows SAPGUI or a Java GUI on Linux/Unix systems.


Can be used for SAP systems with release < 6.20, where external breakpoints are not yet availble.

The connection is opened in debug mode and the invoked function module can be stepped through in the debugger. Possible values:

0: no debugging (default)

1: attach a visible SAPGUI and break at the first ABAP statement of the invoked function module.


For debugging, a SAPGUI needs to be installed on the same machine the client program is running on. This can be either a normal Windows SAPGUI or a Java GUI on Linux/Unix systems.

For backend releases >= 6.20 use external breakpoints instead (see SAP note 668256 Information published on SAP site), as this is more convenient and allows the debugger to run on any host, not only the host on which the RFC client program is running.

Parameters per Connection Type:

Connection Type


RFC server program registered at an Gateway and waiting for RFC calls by an SAP system.

  • DEST = <destination in RfcRegisterServer/RfcStartServe r>

  • TPNAME or PROGRAM_ID = <program ID, optional; default: destination >

  • GWHOST = <host name of the Gateway>

  • GWSERV = <service name of the Gateway>


    In an SAP system, the program ID and this Gateway must be specified in the Destination entry defined with transaction SM59: use connection type T and register mode.

SAP system using load balancing. The application server will be determined at runtime.

  • DEST = <destination in RfcOpenConnection>

  • R3NAME or SYSID= <name of SAP system, optional; default: destination>

  • MSHOST = <host name of the message server>

  • MSSERV = Not needed in most cases. Specify this parameter only, if the message server does not listen on the standard service sapms<SysID>, or if this service is not defined in the services file and you need to specify the network port directly.


    on Unix the services are defined in /etc/services, while on Windows they are defined in C:\WINDOWS\system32\drivers\etc\services.

  • GROUP = <group name of the application servers, optional; default: PUBLIC>

Logon to specific SAP application server.

  • DEST = <destination in RfcOpenConnection>

  • ASHOST = <host name of a specific SAP application server>

  • SYSNR = <SAP system number>

  • GWHOST = <optional; default: gateway on application server>

  • GWSERV = <optional; default: gateway on application server>