Network programming is everywhere these days. It's tough to find an iPhone app that doesn't use the network for something. We also spend a lot of our time abstracted away from the details of networking, using high-level APIs like NSURLConnection. Today I'm going to walk you through the lowest-level API you can find without diving into the kernel, the POSIX sockets API.

In this age of REST and HTTP and massive inefficiency in internet communications, the need for custom network protocols is rare. However, it does happen sometimes, and when it does, I want to make sure it's done right. With that aim, I'm going to discuss some guidelines for designing network protocols, a topic suggested by Mike Shields.

Networking is playing an ever more important role in application development, and Apple's reachability API is a valuable tool in making network-centric apps play nicely with varying real-world conditions. Today I'm going to give an overview of the reachability API, what it does, and how to use it, a suggestion from reader Manuel Diaz.

Reader Steven Degutis was inspired by my post about Distributed Objects and decided to make something that avoided those pitfalls. The result is SocketObjC, a remote messaging library that uses continuation passing style to achieve full asynchronous messaging. I haven't tried it, but it's worth checking out.

It's time for another wintry edition of Friday Q&A. From the comfort of your toasty-warm homes, you can read about building an HTTP server using Grand Central Dispatch, a topic suggested by Steven Degutis.