TCP

Background

Ever encountered a scenario where REST API consumption works from tools like curl, Web Browser but not from Application. Lets dive in.

The requirement is as simple as consuming REST API from a Application over TLS.

Problem Statement

The REST API, to be consumed, is standard API interface which requires access over TLS. The client in this case is Windows 2016 server.

During Development, Windows 10 is used to develop and test the code. Later, the same is tested on a Windows 2016 Server. It is at this stage, it fails with cryptic Error “The request was aborted: Could not create SSL/TLS secure channel”. But it works fine with other tools like curl, PostMan or even from a Web Browser.

Background

I recently had opportunity to support team who has been battling with Intermittent (scary i know :)) issues with TCP connectivity in Production.

Simplified deployment Architecture is as below,

Technology Stack used is Microsoft .NET Framework 4.8 using ODP.NET for Oracle Connectivity (Oracle Server is 8 CPU box). Each of Web Servers in cluster have IIS hosted on it with multiple Applications (Application domains) serving HTTP(s) based traffic. These applications connect to Oracle Database.