Open Source Server Applications
The important open source server applications, which will be discussed in
the following sections include:
Infrastructure services
Web servers
Database servers
Mail servers
Systems management services
7.1 Infrastructure Services
Infrastructure services consist of basic network services, security services,
and file, print, and directory services.
Basic network services include DHCP, DNS, and WINS plus caching
services, and routing where that is not done by an appliance. It is typically
very inexpensive to provide these services, on the order of $100 per user
per year, and this is a commodity activity that any server should be able to
Security services include firewalls, virtual private networking, intrusion
detection, antivirus services, authentication, and authorization. These serv-
ices are difficult to distinguish at times from basic network services and
directory services, which support them, or even mail services, such as the
case of antivirus and antispam services. Active Directory, for example, pro-
vides directory and security services through the same product and the same
interface. Sometimes, indeed increasingly often, these are provided by
146 7.1 Infrastructure Services
A major difference between open source and Windows in this area is
that Linux is usually the operating system of dedicated appliances. Security
is actually the most common single use of Linux in the enterprise, and this
is mostly in appliances. Appliance vendors prefer Linux (or FreeBSD) for
two reasons:
They pay no licensing fees.
They can tune the system precisely for their needs.
As a result, these appliances are inexpensive because of the custom foot-
print and low license fee. Linux networking appliances are also generally
very fast. Linux (along with FreeBSD) is generally recognized to have the
fastest networking stack, and the code can be further tuned for particular
dedicated purposes. Microsoft offers support for appliances also but usu-
ally prefers a more integrated approach, where Windows systems run a mix
of services on a larger server.
7.1.1 File and Print Services
In a mixed environment, we will generally use Samba for file and print ser-
vices. Linux systems also support file sharing very efficiently and easily using
NFS and FTP, and this is a good choice in existing UNIX environments.
Another choice is the Novell iFolders technology, which was recently open
sourced. Given the current distribution of servers and clients, most organiza-
tions are currently using Windows networking, and adopting Samba will be
the simplest choice.
Samba allows non-Windows systems to share file and print services
with Windows systems. Samba clients function like Windows clients, but
for Linux, Mac, or other operating systems, so they see file shares and
printers published by Windows or Samba servers. Samba servers function
like Windows servers, but on Linux or other systems, so they can publish
file and printer shares and also authenticate users in a way similar to a
Windows server. The current version of Samba can authenticate by acting
as a Windows NT primary or backup domain controller, by accessing
Windows NT domain controllers, or by accessing the Windows 2000
Active Directory.
Samba is an efficient program and scales well. Companies such as Bank
of America and Hewlett-Packard use Samba to support many thousands of
clients. The program, written by Andrew Trumbull while at SGI, is an

Get Open Source Software: Implementation and Management now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.