the present invention relates to a method and system for establishing a connection over a network using a technique of web single sign - on . the present invention makes use of an asynchronous engine application that works on the client side ( e . g . an ajax application ) and it is thus possible to eliminate the need for interaction between the reverse - proxy and the back - end application when performing the fsso ( federated single sign - on ) operation . by introducing an intermediary asynchronous engine , e . g . an ajax engine , between the user and the reverse - proxy it is possible that the browser itself can perform the login to the back - end application , thereby offloading this task from the reverse - proxy . with this solution it is even possible to handle initial provisioning and any password - care operations so that the synchronization of registries by external provisioning software is no more needed . a federated single sign - on operation is one under which standardization is used to enable cross domain authentication with a single sign - on name and password . fig1 shows a form based login scenario where a user 100 requests a protected page 102 and the web server 104 redirects the user to a login page ( 106 ). the user is then required to fill in a username and a password 108 and submit the form login to the server . the login page is released if the username and password is authenticated 110 . a reverse proxy may be included and is required to provide an integrated single sign - on solution . the user only logs in to the reverse proxy at the beginning of a session and then is afforded access to multiple web applications without the need for re - authentication . this is shown in fig2 . one or more clients 200 are connected by means of a reverse proxy 202 to one or more web application 204 . in addition , the reverse proxy 202 connects to one or more back - end servers 206 , via a portal server 208 having ports 210 . in this example it is the responsibility of the proxy to automatically perform a login on behalf of the user for each protected application . fig3 shows a technique where a proxy 300 intercepts and processes the authentication challenge 302 from the back - end server 304 , in response to a user request 306 . in this example the proxy server completes the form with the correct account information ( username / password ) to authenticate 310 the user for the relevant back - end application . a user may have different accounts , for example one for each application . if the reverse proxy integrates three back - end applications and there are 100 users identified in the proxy , the proxy should be able to handle authentication for about 400 ( 100 + 300 ) different accounts . typically account information is stored in a user registry such as a database or a light - weight directory access protocol ( ldap ) server . generally the user registry used by the proxy cannot be the same as that used by the back - end application . accordingly , if a single sign - on process is to be successful each time a user wishes it is necessary to implement a synchronization procedure using an external provisioning or metadirectory application as shown in fig4 . in fig4 a password is changed 400 and reported to the synchronization engine 402 . the synchronization engine pushes the password update tot he other systems , for example : notes 404 , nds 406 , databases 408 , oracle 410 , exchange 412 etc . fig5 and 6 show comparisons between a classic web application model and an ajax web application model in order to explain the present invention . in the classic web application model most user actions at the interface trigger an http request 500 from a web server 502 . the server caries out certain processing steps , for example retrieving data , calculations , communications , and then passes an html page 504 to the user . an ajax application eliminates the start - stop nature of interactions on the network by introducing an intermediary device such as an ajax engine 506 between the user 508 and the server 510 . by adding this layer to the application it would seem likely that the process becomes less responsive , however the opposite is actually true . instead of loading a webpage at the start of the session the browser loads an ajax engine . this is written in javascript and is usually in a hidden frame . the ajax engine is responsible for producing the interface presented to the user and communicating with the server on behalf of the user . the ajax engine allows the interaction of the user with the application to happen in an asynchronous manner , which is independent of any communication with the server . as a result , the user is not now presented with a blank browser window or an hourglass icon whilst waiting for the server to do something . each user action that would normally generate an http request takes the form of a javascript call 512 to the ajax engine . any response to a user action that does not require a response from the server is handled directly by the engine . for example , simple data validation , data editing , and even simple navigation may be carried out by the engine . if the engine requires input from the server in order to respond , the engine makes these requests in an asynchronous manner , usually using xml . for example , submitting data for processing , loading additional interface code , or retrieving new data may require server input . referring to fig6 , it can be seen that the overall processing time for specific cycles or actions can be very much reduced by using the ajax engine . this is due to the fact that user requests are handled in an asynchronous manner with the ajax engine . for a classic web application the processing time 600 is much more than that using the ajax engine 602 . the login process in accordance with the present invention is shown in fig7 . fig7 figuratively shows a user screen 700 and an ajax engine 702 forming part of a browser 704 . the browser is in communication with an authentication or reverse - proxy 706 which communicates with a back - end server 708 . at a certain point in time a profiling service 710 may be accessed . in the diagram time increases in the downward direction . the method steps taken will now be described with reference to various actions indicated in fig7 . assuming a user is already authenticated at the proxy , the user may ask for a resource hosted on a back - end server that requires authentication from the back - end , as shown by request 712 . the back - end server requires verification if the request comes from a user which is not authenticated for the back - end server . an authentication challenge is sent back to the user in the form of a login page 714 . the proxy intercepts the login page from the back - end by following a mapping rule and adds a javascript routine 716 in order to load the code for the ajax engine ( not shown ). the browser loads the modified login page 718 and the ajax engine starts to execute the login process in an asynchronous manner with the back - end server as follows . the browser ajax engine displays one or more message 720 to the user , such as “ connecting to protected application ”. in the meantime , the ajax engine contacts the authentication profiling services and requests the user account for the requested back - end application 722 . the authentication profiling services then sends authentication data 724 to the browser in the form of an xml document . the browser ajax engine then augments the authentication xml data and submits a set of credentials via a login form 726 . the login form is received at the back - end server and the credentials are verified in order to finalize the authentication procedure . the back - end server sends the original requested data to the user 728 and the browser ajax engine stop switches off the message “ connecting to protected application ” and displays the requested data 730 . the system can be also be used to automatically maintain the account information of a user and autosynchronize all user registries without needing an external provisioning system and without any user input . a typical situation that can arise is changing a password in the back - end application as a result of expiry of the password . the user does not need to retain the account information for the back - end application since the single sign - on procedure described above can handle this . the password changing process can occur automatically using the ajax engine and without any user interaction . fig8 shows the change of password process which figuratively shows a user screen 800 and an ajax engine 802 forming part of a browser 804 . the browser is in communication with an authentication proxy 806 which communicates with a back - end server 808 . at a certain point in time a profiling service 810 may be accessed . in the diagram time increases in the downward direction . the method steps taken will now be described with reference to various actions indicated in fig8 . assuming a user is already authenticated at the proxy , the user may ask for a resource hosted on a back - end server that requires authentication from the back - end , as shown by request 812 . the back - end server requires verification if the request comes from a user which is not unauthenticated for the back - end server . an authentication challenge is sent back to the user in the form of a login page 814 . the proxy intercepts the login page from the back - end by following a mapping rule and adds a javascript routine 816 in order to load the code for the ajax engine ( not shown ). the browser loads the modified login page 818 and the ajax engine starts to execute the login process in an asynchronous manner with the back - end server as follows . the browser ajax engine displays one or more message 820 to the user , such as “ connecting to protected application ”. in the meantime , the ajax engine contacts the authentication profiling services and requests the user account for the requested back - end application 822 . the authentication profiling services then sends authentication data 824 , to the browser in form of an xml document . the browser ajax engine then augments the authentication xml data and submits a set of credentials via a login form 826 . the login form is received at the back - end server and the credentials are verified in order to finalize the authentication procedure . the proxy intercepts the change password page 828 from the back - end by following a mapping rule and adds the javascript routine 830 for the ajax engine . a modified login page 832 is presented to the user so that new password information 834 can be passed to the profiling server . the browser ajax engine then contacts the authentication profiling services to start a change - password procedure in respect of the user account for the back - end application . the authentication profiling services then generates a new password and stores it in the appropriate use registry . the authentication data with new and old password in the form of an xml document is returned to the browser . the browser ajax engine augments the authentication xml data and submits the change password form to the back - end application 838 . the back - end server processes the data and finalizes the change password / authentication procedure . the back - end server then sends the original requested data 840 to the user whilst the browser ajax engine stops displaying the message “ connecting to protected application ” and instead displays the original requested page to the user 842 . the system can be also used to automatically start a self provisioning operation for those users that have an account on the authentication proxy but do not yet have an account on the back - end server . in general this task can be time and resource consuming , especially where strict account generation policies are implemented using provisioning tools . for example , in situations where management approval of workflow is required . however , there are other situations where such a strict account generation policy is not needed and the application can simply provide a link option to create an account where the user is not yet registered . in this case it is possible to use the present system and method to automatically generate an account without the intervention of the user and without any external provisioning tool . a user does not need to retain account information for the back - end application since the single sign - on procedure described above handle this the initial account process can automatically be carried out using an ajax engine and without any user interaction . fig9 shows the change of password process which figuratively shows a user screen 900 and an ajax engine 902 forming part of a browser 904 . the browser is in communication with an authentication proxy 906 which communicates with a back - end server 908 . at a certain point in time a profiling service 910 may be accessed . in the diagram time increases in the downward direction . the method steps taken will now be described with reference to various actions indicated in fig9 . assuming a user is already authenticated at the proxy , the user may ask for a resource hosted on a back - end server that requires authentication from the back - end , as shown by request 912 . the back - end server requires verification if the request comes from a user which is not unauthenticated for the back - end server . an authentication challenge is sent back to the user in the form of a login page 914 . the proxy intercepts the login page from the back - end by following a mapping rule and adds a javascript routine 916 in order to load the code for the ajax engine ( not shown ). the browser loads the modified login page 918 and the ajax engine starts to execute the login process in an asynchronous manner with the back - end server as follows . the browser ajax engine displays one or more message 920 to the user , such as “ connecting to protected application ”. in the meantime , the ajax engine contacts the authentication profiling services and requests the user account for the requested back - end application 922 . the authentication profiling services then sends authentication data 924 , to the browser in form of an xml document . the browser ajax engine then augments the authentication xml data and submits a set of credentials via a login form 926 . the login form is received at the back - end server and the credentials are verified in order to finalize the authentication procedure and provide the create account page to the client . the browser receives this form and the ajax engine fills in the account creation form fields using the xml data received . the back - end server receives and processes the data 930 and finalizes the account creation procedure and the original data is sent 932 and displayed 934 . from now on the user has an account at the back - end server and the initial password is synchronized in both registries . the ajax engine can be simply be triggered by a javascript function to be included in the page , an example can be as shown in fig1 . the present invention is adaptable to carry out different services . the following is a non - exhaustive list of possible services :