129 lines
5.2 KiB
HTML
129 lines
5.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
|
|
<HTML>
|
|
<HEAD>
|
|
<META NAME="GENERATOR" CONTENT="SGML-Tools 1.0.9">
|
|
<TITLE> NCD X terminal mini HOWTO: Configuring the UNIX Host</TITLE>
|
|
<LINK HREF="NCD-X-Terminal-5.html" REL=next>
|
|
<LINK HREF="NCD-X-Terminal-3.html" REL=previous>
|
|
<LINK HREF="NCD-X-Terminal.html#toc4" REL=contents>
|
|
</HEAD>
|
|
<BODY>
|
|
<A HREF="NCD-X-Terminal-5.html">Next</A>
|
|
<A HREF="NCD-X-Terminal-3.html">Previous</A>
|
|
<A HREF="NCD-X-Terminal.html#toc4">Contents</A>
|
|
<HR>
|
|
<H2><A NAME="s4">4. Configuring the UNIX Host</A></H2>
|
|
|
|
<P>At boot time, the X terminal retrieves files (including its X server
|
|
software) from a remote host on the network. After the terminal boots, the
|
|
X server software will control input, display, local clients and X protocol
|
|
communication. The X server software is executed on the X terminal and
|
|
therefore does not have to be software compatible with the host on which it
|
|
resides.
|
|
<P>
|
|
<H2><A NAME="ss4.1">4.1 TFTP and BootP</A>
|
|
</H2>
|
|
|
|
<P>Together, tftp (trivial file transfer protocol) and BootP (boot protocol
|
|
server) are used on the remote host to allow the X terminal to retrieve its
|
|
X server software and configuration files over the network. Both services
|
|
are typically started by inetd (Internet Daemon).
|
|
<P>
|
|
<P>After the X terminal is powered up, if it is configured to boot from the
|
|
network, it will send out a broadcast message using BootP (TCP/IP bootstrap
|
|
protocol). This boot message will contain the X terminal's hardware
|
|
(Ethernet) address which is used by the boot host to respond to the boot
|
|
request.
|
|
<P>
|
|
<P>When a boot request is received by the remote host, inetd
|
|
(listening on a port designated in /etc/services) starts the BootP daemon
|
|
specified in /etc/inetd.conf.
|
|
<P>
|
|
<P>In file inetd.conf, create or uncomment lines that refer to TFTP and
|
|
BootP. The final argument of the tftpd entry in the example below is the
|
|
path of the directory containing the files required by the X
|
|
terminal. Although directory names are not mandatory, for security reasons
|
|
they should always be present as tftp access will then be restricted to
|
|
files in specified directories.
|
|
<P>
|
|
<P>From a sample file /etc/inetd.conf:
|
|
<PRE>
|
|
# tftp service is provided primarily for booting. Most sites
|
|
# run this only on machines acting as "boot servers".
|
|
tftp dgram udp wait root /usr/sbin/tcpd /usr/sbin/in.tftpd /usr/X11/lib/X11/ncd/
|
|
bootps dgram udp wait root /usr/sbin/tcpd /usr/sbin/in.bootpd
|
|
</PRE>
|
|
<P>
|
|
<P>Upon activation, the BootP server daemon on the host will then read its
|
|
database file /etc/bootptab. An entry for the X terminal must be placed in
|
|
this file. Each entry contains a set of tags separated with ':'
|
|
characters. The host name must be the very first tag in an entry.
|
|
<P>Useful bootptab tags:
|
|
<DL>
|
|
<DT><B><B>hd</B></B><DD><P>Bootfile home directory (eg /usr/X11/lib/X11/ncd/).
|
|
<DT><B><B>ip</B></B><DD><P>Address of the X terminal (eg 10.0.0.1).
|
|
<P>
|
|
<DT><B><B>sm</B></B><DD><P>Subnet mask (eg 255.0.0.0). To understand the use of
|
|
the subnet mask and other IP networking principles, consult the Linux NET-3
|
|
(networking) HOWTO document.
|
|
<P>
|
|
<DT><B><B>gw</B></B><DD><P>IP Address of gateway (eg 10.0.0.1).
|
|
<DT><B><B>ht</B></B><DD><P>Hardware type - Ethernet in this example.
|
|
<DT><B><B>ha</B></B><DD><P>Hardware address of X terminal (6 byte Ethernet address)
|
|
<P>According to the bootptab UNIX man page, the 'ha' tag must be preceded by
|
|
the 'ht' tag. The X terminal's Ethernet address is displayed when the
|
|
terminal is first powered on. The address appears as a series of 6
|
|
double digit hex numbers separated by colons (e.g. 00:00:A7:12:26:19).
|
|
<P>
|
|
<DT><B><B>tc</B></B><DD><P>Table continuation or label of another entry in the
|
|
BootP database. See the example below.
|
|
<P>
|
|
<DT><B><B>ds</B></B><DD><P>IP address of domain name server (eg 10.0.0.3). Not
|
|
required if DNS is not used for hostname resolution.
|
|
<P>
|
|
<DT><B><B>bf</B></B><DD><P>Name of X terminal boot file (Usually the terminal
|
|
model is used as the X server file name eg Xncd19r).
|
|
</DL>
|
|
<P>
|
|
<P> The following is an example of the Boot protocol server database file,
|
|
/etc/bootptab. The character '\' is used to escape the end-of-line
|
|
character.
|
|
<P>
|
|
<PRE>
|
|
# This is an entry (here given the name default)
|
|
# with information common to all BootP clients
|
|
default:hd=/usr/X11/lib/X11/ncd/:\
|
|
ds=10.0.0.3:\
|
|
sm=255.0.0.0:\
|
|
gw=10.0.0.1:
|
|
|
|
# X terminal entry with hostname myxterm
|
|
# Notice the tc tag reference to the entry default
|
|
myxterm:ht=ethernet:\
|
|
ha=0x0000a7122619:\
|
|
ip=10.0.0.2:\
|
|
tc=default:\
|
|
bf=Xncd19r:
|
|
</PRE>
|
|
<P>
|
|
<P>When a matching entry for the hardware address in the boot request is found
|
|
in the bootptab file, a response is sent by bootpd with the corresponding
|
|
IP address from the matching entry. File transfer can then take place over
|
|
IP using TFTP.
|
|
<P>A hostname can be assigned to the X terminal by creating an entry on
|
|
the boot host in the file /etc/hosts. This file is used to map hostnames to
|
|
IP addresses. In the this example, the X terminal (address 10.0.0.2) has
|
|
been assigned the hostname 'myxterm'.
|
|
<P>
|
|
<PRE>
|
|
10.0.0.1 linuxhost # The boot host
|
|
10.0.0.2 myxterm # X terminal
|
|
</PRE>
|
|
<P>
|
|
<HR>
|
|
<A HREF="NCD-X-Terminal-5.html">Next</A>
|
|
<A HREF="NCD-X-Terminal-3.html">Previous</A>
|
|
<A HREF="NCD-X-Terminal.html#toc4">Contents</A>
|
|
</BODY>
|
|
</HTML>
|