ora-12571

What does error ORA-12571 (TNS:packet writer failure) mean in a Web Service?

Background: I'm calling a Web Service written in ASP.NET that queries an Oracle database. I know the Web Service itself works, because I've used it before other applications. So I have a web application in Visual Studio that I've been switching back and forth to point from a 'DEV' web service to a production configured version of the s...

What is the difference between "ORA-12571: TNS packet writer failure" and "ORA-03135: connection lost contact"?

I am working in an environment where we get production issues from time to time related to Oracle connections. We use ODP.NET from ASP.NET applications, and we suspect the firewall closes connections that have been in the connection pool too long. Sometimes we get an "ORA-12571: TNS packet writer failure" error, and sometimes we get "O...