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inetd Configuration File

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The Internet daemon accesses the configuration data it needs by reading the file /etc/inetd.conf in the POSIX name space. When you install or update to version C.60.00 of MPE/iX, you receive a sample configuration file that you can use as a template for your own inetd configuration file if you don't already have one. This process involves two steps: creating the actual file in the MPE name space and creating a symbolic link that points from the POSIX file /etc/inetd.conf to the MPE file. The steps to create and link the file is explained later in this section. The reasons Hewlett-Packard recommends symbolic linking is explained in Chapter 1 "Introduction to Internet Services"

The Internet daemon reads its configuration file on three occasions:

  • When inetd is started during normal system startup

  • When inetd is started following a network shutdown as opposed to a system shutdown

  • When you instruct an executing inetd to reread the configuration file after you have made changes to it that you wish to put into effect

Creating and Linking inetd Configuration File

You may already have a configuration file for inetd installed on your system. If you know that you have such a file, and it is accessible by the POSIX file name /etc/inetd.conf you may skip these steps.

If not, follow these steps to create the file and link to it. If you have such a file, but are unsure whether or not it is linked, perform step 2 only.

  1. Create your own configuration file by using the COPY command to rename the sample file. Enter:

    :COPY INCNFSMP.NET.SYS TO INETDCNF.NET.SYS

  2. Create a symbolic link from /etc/inetd.conf in the POSIX name space to INETDCNF.NET.SYS. Enter:

    :NEWLINK /etc/inetd.conf, INETDCNF.NET.SYS

  3. Check the security provisions of the file and change them, if necessary. Hewlett-Packard recommends that only MANAGER.SYS has write access to INETDCNF.NET.SYS, and write and purge access to /etc/inetd.conf.

Adding New Services to inetd Configuration

There are two steps required to add a new service to the suite of Internet Services offered on your system. First you enter a line of information for the specific service to the inetd configuration file. Then you have inetd reread its configuration file, which is sometimes called reconfiguring the Internet daemon. In the unlikely event that inetd is not running when you edit the configuration file, you will invoke the new configuration by starting inetd. Starting inetd is explained later in this chapter.

To edit the inetd configuration file, do the following:

  1. Open the configuration file with an MPE text editor.

    The contents will resemble the following: 

    
 ##################################################################
 #
 # sample inetd configuration file
 #
 # For information on how to configure this file refer to the
 # Configuring and Managing Internet Services manual
 #
 # Note: The entries cannot be preceded by a blank space. Blank
 # lines and lines beginning with a pound sign(#) are ignored.
 #
 ##################################################################
 #
 # Internet server configuration database
 #
 echo         stream tcp nowait MANAGER.SYS internal
 echo         dgram  udp nowait MANAGER.SYS internal
 daytime      stream tcp nowait MANAGER.SYS internal
 daytime      dgram  udp nowait MANAGER.SYS internal
 time         stream tcp nowait MANAGER.SYS internal
 time         dgram  udp nowait MANAGER.SYS internal
 discard      stream tcp nowait MANAGER.SYS internal
 discard      dgram  udp nowait MANAGER.SYS internal
 chargen      stream tcp nowait MANAGER.SYS internal
 chargen      dgram  udp nowait MANAGER.SYS internal
 #telnet      stream tcp nowait MANAGER.SYS internal
 #bootps      dgram  udp wait   MANAGER.SYS /SYS/NET/BOOTPD bootpd
 #tftp        dgram  udp wait   USER.TFTP /SYS/NET/TFTPD tftpd
 #

  2. Each of the services that run under inetd must have an entry in the configuration file. For example, the entry for the tftp program in INETDCNF.NET.SYS looks like this: 

    
  tftp  dgram  udp  wait  USER.TFTP     /SYS/NET/TFTPTD     tftpd
    For the service that you are installing, check the file to see if it has the correct entry. (Each chapter in the remainder of this manual has this information. The meaning of the individual fields in an entry are explained later in this chapter.) If not, enter the line now using the "Editing Tips" section, as a guideline.

    NOTE: For more information on FTP, refer to Installing and Managing HP ARPA File Transfer Protocol Network Manager's Guide or HP ARPA File Transfer Protocol User's Guide.

  3. Save the file and exit the editor program.

  4. Signal inetd to reread the configuration file by entering the following command at the CI prompt:

    INETD.NET.SYS -c

    Or you may enter this command from the POSIX shell:

    $/etc/inetd -c

Editing Tips

When you are editing the inetd configuration file, keep in mind these points:

  • If you find the line, but it has been "commented out" (that is, preceded by a pound sign, #), the service has not yet been enabled. To enable it, simply delete the pound sign and any spaces that precede the service name.

  • If you need to type the line into the file:

    • Use only lowercase characters

    • Enter the service name in the first column without any leading spaces

    • Separate the individual fields on the line with any number of blanks or tab characters to improve readability

Fields in an inetd Configuration File Entry

Each entry in the inetd configuration file conforms to a common format in which each of the fields has a specific purpose. For example, the entry for TFTP looks like this: 

  tftp  dgram  udp  wait  USER.TFTP     /SYS/NET/TFTPD     tftpd
Reading an entry from left to right, these fields are:
Field

Purpose

service name

The name of the service in the services file.

socket type

Either stream if the socket is a stream socket, or dgram if the socket is a datagram socket.

protocol

A valid protocol name, either tcp or udp, as entered in the protocols file.

wait state

One of two states, wait or nowait, that applies only to datagram sockets. The wait entry instructs inetd to execute only one datagram server for the specified socket at any one time. This is a single-threaded datagram server. The nowait entry instructs inetd to execute a datagram server for a specified socket whenever a datagram arrives, which frees the socket so that inetd can receive further datagrams. This is a multi-threaded datagram server.

user

The identification of the user when the server is running.

server program

The absolute path of the program that inetd executes when it receives a connection request.

arguments

Arguments to the server program, beginning with argument zero, which is the name of the program.



Overview of inetd

inetd Security File