RSC/MP 7.2 Programming Manual
Access Control Server
HP NonStop Remote Server Call (RSC/MP) Programming Manual—522360-004
9-2
How ACS Works
Mapping of RSC/MP sessions to ACS objects can be done in either of two ways:
•
In the TDP (recommended) by setting the TERM object’s ACSERVER attribute to 
the name of the ACS object. This approach provides stronger security because it 
does not rely on the RSC/MP application to supply the name of a properly 
configured ACS object.
•
In the RSC/MP application by setting the HOST_ACS_NAME option to the name of 
the ACS object that should control access. This option must be set prior to the 
RscBeginSession call.
How ACS Works
The ACS facility works as follows:
•
At the start of an RSC/MP session (when the application calls RscBeginSession), 
the TDP determines whether an ACS is configured for that workstation.
•
If an ACS is configured, the TDP sends the USER_ID and PASSWORD from the 
header of its RscBeginSession message to the ACS. The user ID and password 
come from the workstation options.
•
If the USER_ID and PASSWORD options are accepted by the ACS, the TDP starts 
the session.
An ACS object has two additional levels of access control. These controls are 
determined by the ACS program and by the RECVWRITEREADS attribute of the ACS 
object:
•
The USER_ID and PASSWORD can be validated on each RscWriteRead, which is 
enabled by setting the RECVWRITEREADS attribute of the ACS object to YES. 
•
When the TDP receives an RscBeginSession message, the user-written ACS can 
reply with a list of authorized servers. This list, maintained for each session, 
contains the names of stand-alone servers and Pathway server classes. The TDP 
checks the list to allow or block access (depending on the settings used by the 
ACS) to the servers named in each subsequent RscWriteRead or RscWrite 
function call. 
The TDP can be configured to report successful and/or rejected ACS attempts on each 
RscWrite or RscWriteRead. The logging of ACS status on an RscWrite/RscWriteRead 
basis is configured in a TERM object using the option TERM LOGEVENTS 
ACSALLOW to log successful attempts and the option TERM LOGEVENTS 
ACSREJECT for rejected attempts. Refer to the HP NonStop Remote Server Call 
(RSC/MP) Installation and Configuration Guide for information on setting up TERM 
LOGEVENTS as part of TDP Logging.
Note. The ACS mechanism provides application-defined security. The USER_ID and 
PASSWORD options are passed to an ACS only. They are not related to Guardian 
security, unless you choose to make use of Guardian security functions in your ACS 
implementation.










