If you have a Windows domain installation of Informix Dynamic Server, and there are a large number of trusted domains in your network, connecting to IDS with a non-existant user it can take a long before the expected -951 error is returned. This happens because the Windows API function to lookup the account name can check all trusted domains if a domain name is not specified. The larger the domain forest, the longer the failed connection can take.
This problem has been logged as APAR 34657782 and it should be fixed very shortly. A workaround is to always fully qualify the user name by specifying domain\username at connection time.
Random grainy cellphone snap of the day:
Roppongi at night
Connecting with an invalid username can be slow on Windows