Palm OS Network Programming

Chapter 7. Hostnames and Addresses

Now that we’ve connected to the network, we can start accessing network services such as FTP servers, web sites, and electronic mail. In order to access one of these services, we need to connect with the host on which it runs and the process on that host that provides that service. Before we can connect with this host and process, we need to identify them.

In this chapter, we discuss hostname resolution, the process through which hosts are identified. We also examine service resolution, which identifies the appropriate process on that host, such as an FTP server or chat peer. And we see how the Palm OS Net Library supports name and service resolution. Along the way, we discuss general networking issues as they arise from the standpoint of how these are solved with the Net Library.

Hostname Resolution

Let’s say you wanted to call me on the phone. You would need my phone number, since it uniquely identifies me on the telephone network. So when you dial my number, only my phone rings. But what if you don’t know my phone number?

You could call directory assistance or look me up in the phone book. These methods bridge the gap between humans and the telephone network. The telephone network understands phone numbers, humans prefer names.

Network applications face the same challenge. Like phone networks, computer networks prefer to work with numeric addresses. On TCP/IP networks, such as the Internet, a host’s address is represented as a 32-bit integer, ...