I have been tracking down some difficult connection problems with a BlackBerry application I have written. The main problem is that there are so many ways that a BlackBerry application can connect (TCP, WAP2, BIS, BES) and different ways that the BlackBerry can be configured (via the Service Book) that it can be difficult to have all the cases covered.
A tip I have is to use the BlackBerry Network Diagnostic Tool that BlackBerry made available earlier this year. It allows you to test the various types of connection against a chosen web site. The results can be emailed so it’s easy to run on an test user’s phone and have them send you the results. However, there are three problems. The first is that the diagnostic tool is only provided in source code form. The second problem is that compiling it requires that you have Java signing keys. Finally, the source code, as supplied, only compiles under 4.5 or later while many developers will be using 4.2 to maximise compatibility.
As a service to the mobile developer community I have solved all these problems and a download is available at http://www.surerange.com/NetworkDiagnostics.jad (Linux server so case sensitive!). Enter the URL into your BlackBerry web browser and it will download the .jad, confirm download then download the .cod.