MobiLink includes a web server extension called the Redirector that routes requests and responses between a client and the MobiLink server. A plug-in such as this is also commonly called a reverse proxy.

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 server.

See Options when using a web server.

Using the Redirector, you can configure your web server to route specific URL requests to one or more computers running the MobiLink server.

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.

Load balancing and failover

The Redirector implements load balancing and failover using a simple round robin algorithm (servers are chosen in a fixed cyclic order). The Redirector pings each MobiLink server and stops sending requests to a server that is not responding. The Redirector detects when a MobiLink server is running again and resumes sending requests at that time.

HTTPS synchronization

When you specify the HTTPS protocol on a MobiLink client, HTTPS is used for the connection between the remote database and web server: HTTP headers are encrypted over TLS using RSA encryption before being sent to or from the web server, and the web server decrypts the HTTPS and sends HTTP to MobiLink via the Redirector. All Redirectors support this version of HTTPS, in which HTTPS is only used for the connection between the MobiLink client and the web server.

The HTTPS protocol is slower than other secure protocols.

Full HTTPS

For some Redirectors (such as the Apache Redirector, the ISAPI Redirector, and the NSAPI Redirector on Windows), the Redirector offers an option to re-encrypt the stream as HTTPS and send it to the MobiLink server.

For a list of Redirectors that support HTTPS from the Redirector to the MobiLink server, see  SQL Anywhere Supported Platforms and Engineering Support Status.

Supported web servers

Plug-ins are provided for the following web servers:

For more information about Redirector support, see:

•  SQL Anywhere Supported Platforms and Engineering Status