With 4D's web server, the session management keeps track of the IP address for validation and maintaining the session. With mobile and portable devices it can be highly likely that network access points and hosts can change, which will also change the IP address of the device and will disrupt the session.

This feature is enabled by default, to avoid this issue the the IP address validation can be turned off by calling the WEB SET OPTION command with the 83 selector (constant Web Session enable IP address validation) and setting the value to 0 to disable the feature or 1 to enable the feature.

Example:

WEB SET OPTION(Web Session enable IP address validation;0) //Will turn off the IP address validation