TouchSocket is an integrated .NET networking framework that includes modules for socket, TCP, UDP, SSL, named pipes, HTTP, WebSocket, RPC, and more. It offers a one-stop solution for TCP packet issues and enables quick implementation of custom data message parsing using protocol templates.

WatsonTcp is the easiest way to build TCP-based clients and servers in C#.

Simple wrapper for TCP client and server in C# with SSL support

Asynchronous TCP .NET library with reliable transmission and receipt of data, with an ssl implementation.

Vaser is a powerful high performance event based network engine library for C# .Net. It’s possible to start multiple servers in one program and use the same network code for all servers. In the network communication are all strings are omitted, instead it is based on a unique binary identifier, which the CPU and memory relieves massively.

FTPS Client ftp over ssl

Project demonstrating HTTP Public Key Pinning (HPKP) security feature between a server (Node.Js Expess Application) and a client (C# Console Appllication)

TLS HttpWebRequest in .NET 4.0 using Thumbprint Pinning