01283 500255 enquiries@sfl.co.uk





The two main methods of using the CREST Simulator are:

  • The File Transfer Interface, used to send both DEX formatted files to/from the service using FTP,SFTP or HTTPs
  • The SimGUI web portal via simgui.sfl.co.uk

The following sections explain how to connect to both.



In the real CREST environment, access is achieved through the SWIFT or BT Settlenet secure networks.  The CREST Simulator differs, in that access is provided over the internet using encrypted transfer protocols imitating either SWIFT or BT methods.

There are a number of options for connecting to the Simulator:

Connection Option 1: Safe Gateway Applications
These applications manage the transfer of files between local/remote locations.   The software is normally installed on a server which can be left running to support multiple users using the Simulator service.

The two main applications are:

  • Secure Gateway : A small VB application that utilises SFTP or FTP to transfer files and can be installed on any version of Windows.
  • Safe Gateway Manager : A java application that uses encrypted HTTPS transfers which can be directed via a web proxy service to remain inline with corporate IT policies.    This software can be installed on Windows or Linux servers.

The following illustrates a typical file transfer configuration using a Secure Gateway as an example:


  1. The back-office system generates files which are picked by the SF Gateway via a mapped drive.
  2. The Gateway transfers the files over the internet using encrypted protocols to the SF Gateway Server.
  3. The CREST Simulator processes the files from the customer and deposits response files back onto the Gateway Server.
  4. The SF Secure Gateway app polls the Gateway Server to pickup the processed files and deposit them on the back-office system.

NOTE: All connectivity is controlled by the customer and at no point do SFL require network access to customers systems.

To facilitate all customers, the software is highly customisable. If you have any queries or questions please contact us.

Connection Option 2: Customer Controlled File Transfers

Customers access the service directly, if SFTP or FTP protocols are supported.   In these circumstances, no software is needed on the customer site.

Connection Option 3: Customer Controlled File Server

Customers provide access to their own SFTP server and SFL manage the flow of files between the customer and the service.    In these circumstances, no software is needed on the customer site.

In some circumstances the file transfer process between the test system and the service can only be achieved through the use of multiple gateways. The SF Secure Gateway will manage the transfer of files both between the backoffice and inhouse software gateway and the CREST Simulator service.

The CREST Simulator and software Gateways can support multiple customer environments within the same file transfer application. For example you can have Unit Test, Regression Test and UAT Environments running through the same instances.

SF Gateway application supports;

  • FTP on port 21/22 : A none encrypted file transfer protocol mainly used in legacy systems.
  • SFTP on port 22 : Password or private/public key Authentication and encryption of all traffic
  • HTTPs.   A proxy friendly transfer application that transfers files using 256bit encryption





The SimGUI is an invaluable, web based portal into the CREST Simulator environment.

When connecting to the CREST Simulator, SFL will provide customers with their Gateway Credentials. These credentials are used to register a users email address within the SimGUI. With customer permission, SFL permit access to a gateway by 3rd parties and software houses associated with the customer.

The following diagram depicts the SimGUI and CREST Simulator.


If you would like to find out how the Simulator Service can help your system testing, training and development, please complete the below to request a month’s trial.

Safe Financials Ltd

1st Floor Waverley Court
Wiltell Road
WS14 9ET

01283 500255