The Sockets Networking API: UNIX® Network Programming Volume 1, Third Edition

Chapter 11. Name and Address Conversions

Introduction

All the examples so far in this text have used numeric addresses for the hosts (e.g., 206.6.226.33) and numeric port numbers to identify the servers (e.g., port 13 for the standard daytime server and port 9877 for our echo server). We should, however, use names instead of numbers for numerous reasons: Names are easier to remember; the numeric address can change but the name can remain the same; and with the move to IPv6, numeric addresses become much longer, making it much more error-prone to enter an address by hand. This chapter describes the functions that convert between names and numeric values: gethostbyname and gethostbyaddr to convert between hostnames and IPv4 addresses, and getservbyname ...