This topic guides you through the steps required to configure an 
               		enterprise server region with Mainframe Subsystem Support to enable ELF functionality. The region must be secured with a Security Manager which allows
               you to generate and sign on with passtokens. See 
               		ESF Passtokens for more information. 
               	 
            
 
            	 
            You must add a new DCAS listener to the region: 
               	 
            
 
            	 
             
               		
               - Start the Enterprise Server Administration home page, and then click 
                  		  Edit for the region you want to create the listener for. 
                  		
               
- Click the 
                  		  Listener tab, and then click 
                  		  Add. 
                  		
               
- In the 
                  		  Support Conversation Type group, click 
                  		  Custom. 
                  		
               
- In the field next to the 
                  		  Custom option, type 
                  		  dcas. 
                  		
               
- Configure the listener as required. DCAS listeners must be configured for SSL communication. See 
                  		  DCAS conversation type and 
                  		  Secure Communications (SSL) for more information. 
                  		  
                  Note: Micro Focus recommends you configure both the DCAS and TN3270 listeners with the same SSL server certificate and key. Failure to do so
                     might result in users being able to incorrectly acquire or fail to acquire passtokens from DCAS. 
                     		  
                   
-  Use the cascertreg command line utility to map a user certificate to a user ID. You can do this by using the command line
                  utility cascertreg. See 
                  		  cascertreg for more information. 
                  		  
                  Note: Regions that use certificate mapping for CICS Web Interface can use the same certificate mappings for DCAS. 
                     		  
                   
- You might need to perform additional configuration for an existing TN3270 listener, either to configure SSL or explicitly
                  reference a DCAS connector. Depending on how your users' certificates are created, you might need to configure the 
                  		  Maximum Chain Length and 
                  		  Match Client Hostname settings. See 
                  		  To set certificate validation options and 
                  		  TN3270 conversation type for more information. 
                  		
               
Once these steps are complete, users need to configure their clients to allow ELF negotiation, also referred to as Certificate
               Express Logon (CEL), and to connect using their certificate. Once this is done the user is able to log on to the server using
               their certificate as identification. The logon process itself is often performed using a macro which inserts the two well-known
               placeholder strings into the logon fields, which the server sees and replaces with the mapped username and passtoken. These
               strings are: 
               	 
            
 
            	 
             
               		 
               		  
               - ")USR.ID(" 
                  		  
               
- For the username. 
                  		  
               
- ")PSS.WD(" 
                  		  
               
- For the password.