Chapter 30. Configuring and Managing ARPABerkeley Services | HP Certified: HP-UX System Administration

Chapter 30. Configuring and Managing ARPA/Berkeley Services

Chapter Syllabus

30.1 Introduction to Internet Services

30.2 Starting and Managing Internet Services

30.3 Using SAM to Manage Network Services

ARPA and Berkeley services are the most widely used network applications on HP-UX networks or any other modern UNIX platform. The ARPA services are commonly used on the Internet and are also available on operating systems other than UNIX. Berkeley services, on the other hand, are mostly available only on UNIX systems, with few exceptions. Collectively, ARPA and Berkeley services are also called Internet services. Applications based on these services are used for file transfer, remote login, routing, electronic mail, and other network- related activities.

These Internet services are used in the client/server model. A server offers some of its resources to clients. The client and server communicate with each other on a network by using ports and sockets. Well-defined ports are used for standard services. A common user of HP-UX utilizes only clients for these services. The server services are configured by the system administrator and are started at system boot time. One HP-UX system may be running many server applications simultaneously . As an example, a single HP-UX system can act as a mail server, an FTP server, and a domain name server, all at the same time. A system may also act as client and server at the same time where server applications are running as background processes while a user is using a client application.

HP-UX includes utilities for both ARPA and Berkeley services. These server applications are configured to run a daemon or through inetd . When a service is started as a daemon, it starts listening to incoming client requests on its designated port. If a service is started using the inetd daemon, it listens to all ports for the services configured through it. When a client sends request for a particular service, the server process is initiated by inetd . The server and client then establish connection with the help of sockets. The network services have their own security features that can be used to selectively allow or deny hosts and users access to local resources.

In this chapter, we will start with a list of available services and how to configure and start these on HP-UX. We will then look into the formats of some of configuration files used with these services. We will also discuss some security issues of different services. SAM will also be used to configure some service daemons.

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