Troubleshooting Common Problems


There can be many things that interfere with TCP/IP communications!

(c) 2007-2008 Hermetech International Ltd.

1) Diagnosing application problems can be a tricky issue. The #1 support call received here at HermeTech about ANY of our TCP/IP products is because of a lack of knowledge of DEP (Data Execution Prevention) and how it is used in MS Windows operating systems beginning with MS Windows XP service pack 2 and MS Windows Server 2003. For more info on DEP click HERE. This API opens and closes TCP/IP sockets and sends and receives data over TCP/IP it may trigger DEP and cause Windows to close the application. If you receive fatal errors which close the application or cause the service to stop unexpectedly verify that DEP is not the culprit first! It will almost certainly trigger any network security software (such as Norton or Symantec) so be prepared to instruct users how to handle these events.


2) Firewalls and 3rd party network monitoring software, including the Windows Firewall as well as Norton's and Symantec's virus scanning and network protection suites can cause problems depending on how they are configured. You may need to add your program as exceptions in these types of systems.


3) If Calls to StartListening() fail verify that you are passing a valid port number AND that no other application is currently listening on that port on that computer.


4) If no messages are being forwarded from the UltraPort Listener verify that the Listener Profile has the correct information in the Proxy Settings. If your application is running on a different computer then be sure and verify that the Listener Profile has the correct TCP/IP address for the application computer. You can also verify that the connection between your application and the UltraPort Listener is not being blocked by any 3rd party software or firewalls or hardware routers.



See also: Frequently Asked Questions