This section discusses some steps you can take to diagnose system signon problems. Understanding basic operations and process flow is essential when you are troubleshooting connectivity errors. Use the following model as a reference for this section.
Test terminal connection.
Try using TELNET, or a similar network utility, to get a terminal connection to your database server. If this succeeds, you probably have a problem with the way Informix-Connect or Informix is set up. Check to see if the Informix database server is active. If Step 2 fails, then the problem is within the networking layer.
Consult your networking experts.
The problem has been isolated to something within the network layer. Try to isolate the network problem. Can you log on to other servers? Are other terminals still able to connect? Try lowering level network diagnostics, if they exist