MobiLink Synchronization User's Guide
Synchronizing Through a Web Server
MobiLink includes a web server extension called the Redirector that routes requests and responses between a client and the MobiLink synchronization server. A plug-in such as this is also commonly called a reverse proxy.
Using the Redirector, you can configure your web server to route specific URL requests to one or more computers running MobiLink synchronization server. The Redirector also implements load-balancing and failover: each MobiLink synchronization server is tested at set intervals and requests are no longer sent to a server that is not responding. It also detects when a MobiLink synchronization server is running again and resumes sending requests at that time.
Web servers can be configured to pass requests with specific URLs or ranges of URLs to extension programs commonly written in the form of perl CGI scripts, DLLs, or other extension mechanisms. These extension programs may access external data sources and provide responses for the web server to deliver to its clients.
This chapter describes one way to set up MobiLink synchronization across a firewall, with the MobiLink synchronization server running inside the firewall, and the MobiLink clients outside the firewall. Synchronization is routed through a web server.
The main reason for routing requests through a web server is to use existing web server and firewall configurations for HTTP or HTTPS synchronization. However, a web server can operate as a proxy without the Redirector. The Redirector is most useful when you have more than one MobiLink synchronization server.
In HTTPS synchronization, HTTP headers are encrypted over SSL/TLS using RSA encryption before being sent to or from the server. HTTPS is only used for the connection between the MobiLink client and the web server. The web server decrypts the HTTPS and sends HTTP to MobiLink via the Redirector.
The HTTPS stream is slower than other secure streams, so it is recommended that it be used only if the HTTPS protocol is required.
Plug-ins are provided for the following web servers:
Netscape iPlanet web servers (the NSAPI Redirector)
Microsoft web servers (the ISAPI Redirector)
Web servers that support the Java Servlet API 2.2 (the servlet Redirector)