Thin Client: New User Guide
 Stephen Noble stephen7 at bigfoot.com
 30th November 1999

 1.How to turn inexpensive legacy computers into fast terminals using
 the power of your main computer, you will need : A fast computer to
 act as Server, A client computer (old and unwanted). Linux compatible
 network cards. A connection between computers.  2.How to centralise
 system administaration by useing NFS, ie placing the entire file sys-
 tem of a faster client on the server.
 ______________________________________________________________________

 Table of Contents


 1. Introduction

 2. Hardware and Documentation

    2.1 Hardware
    2.2 Documentation

 3. Server setup

    3.1 Check your network services on your server
    3.2 Setting up a dhcpd daemon
    3.3 Tftpd setup
    3.4 Kernel image
    3.5 Security

 4. Client setup

 5. Network files system

    5.1 server specific
    5.2 client specific

 6. X-terminal

 7. Acknowledgments & further exercises



 ______________________________________________________________________

 11..  IInnttrroodduuccttiioonn


 +o  Linux allows any reasonably new computer to be used as a server to
    a thin client, or many thin clients, these thin clients can be
    inexpensive legacy computers. For a console terminal you need a 386
    with 4-8mb of ram, or for an X-Terminal a 486/66 with 8-16mb ram.

 +o  One Option is without a hard drive, it keeps the noise down and
    simplifies administration as you only have one system to maintain.

 +o  If you have legacy apps, you can have them on a hard drive with
    it's legacy Operating System

 +o  This howto is aimed at those new to Unix/Linux, it will cover the
    essential areas you need to be aware of and point you to other
    documentation in that area you need to be familiar with.

 +o  You will probably use this as an aid to the
    http://www.slug.org.au/etherboot/  documentation, I include some
    more examples of config files, and leave many of the other features
    of etherboot as an exercise for the reader

 +o  If your client is sufficiently powerful only the file system need
    be shared, applications can run on the client system. (say a 233
    32mb ram).  Install an application on the server and all clients
    have access



 22..  HHaarrddwwaarree aanndd DDooccuummeennttaattiioonn


 22..11..  HHaarrddwwaarree

 When you start, you will need at least this



 +o  a computer to act as Server,

 +o  a client computer, I unplugged the power to the hard disk and
    disabled the drive in the bios to emulate a diskless machine

 +o  compatible network cards

 +o  connection between computers, I used twisted pair ethernet with
    RJ45 terminators

 +o  For two computers a _c_r_o_s_s_-_o_v_e_r _c_a_b_l_e  is sufficient, and saves
    another power point, the first computer shop I went to gave me
    blank stares, idiots !

 +o  For two or more clients, you need a hub, a kit with a 10 mb 4 port
    hub ,2 cards sells for under A$150, you can probably do better,
    I've had some success with $5 second hand cards, 3m cables for $6,
    a new hub for $40, a found monitor and a $60 pentium 75


 22..22..  DDooccuummeennttaattiioonn

 You may like to familiarise yourself with the linux documentation,
 specifically you can read (skim) for an overview the following :


 +o  /usr/doc/HOWTO/mini/Diskless - a similar howto tackling this
    problem

 +o  Networking Overview HOWTO - Networking capabilities of the Linux

 +o  Ethernet HOWTO -  Information on Ethernet hardware compatibility

 +o  NET-3 HOWTO -  How to configure TCP/IP networking under Linux.


 Also you probably have in the  /usr/doc/LDP/ directory

 +o  The System Administrators' Guide

 +o  The Network Administrators' Guide

 +o  Linux Installation and Getting Started


 The obligitory link


 +o  http://www.magma.ca/~bklimas help for new linux users.


 One last thing

 +o  my network server is snoball , my client is elite and my
    (local)domain is gundog.net Replace with your computers names where
    applicable


 33..  SSeerrvveerr sseettuupp

 The server needs to be setup in readiness for the client in a number
 of ways


 33..11..  CChheecckk yyoouurr nneettwwoorrkk sseerrvviicceess oonn yyoouurr sseerrvveerr

 run the command /sbin/ifconfig if your output is similar to below then
 your loopback and ethernet card are correctly configured.


 ______________________________________________________________________
 [cassie@snoball cassie]$ /sbin/ifconfig
 lo        Link encap:Local Loopback
      inet addr:127.0.0.1  Bcast:127.255.255.255  Mask:255.0.0.0
      UP BROADCAST LOOPBACK RUNNING  MTU:3584  Metric:1
      RX packets:854 errors:0 dropped:0 overruns:0 frame:0
      TX packets:854 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0
 eth0      Link encap:Ethernet  HWaddr 00:AA:00:BB:BD:09
      inet addr:192.168.53.1  Bcast:192.168.53.255  Mask:255.255.255.0
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:190369 errors:0 dropped:0 overruns:0 frame:0
      TX packets:249267 errors:0 dropped:0 overruns:0 carrier:1
      collisions:4793           Interrupt:5 Base address:0x320
 ______________________________________________________________________




 If not ...

 +o  loopback, if this isn't here you need to activate it at start up,

 +o  ethernet card, is it being detected,is the driver a module

 +o  you can set these in linuxconf or netcfg


 33..22..  SSeettttiinngg uupp aa ddhhccppdd ddaaeemmoonn

 Here the server gives out IP numbers to requests by clients


 +o  is DHCPD installed, maybe (as root) just run ntsysv and have it
    start at boot time

 +o  this /etc/dhcpd.conf file assigns static IP numbers if you have a
    matching MAC address, A MAC address is a unique 'number' given to
    the NIC.  The start of the 'number' is based on the manufacturer,
    if you don't have a sticker on the card, attempt to load the rom
    image from eprom or floppy and see what it reports. (see client
    setup)


    ___________________________________________________________________
    #/etc/dhcpd.conf
    subnet 192.168.35.0 netmask 255.255.255.0 {
        option domain-name "gundog.net";
        range dynamic-bootp 192.168.35.128 192.168.35.255;
        default-lease-time 21600;
        max-lease-time 43200;
        }

    host 286 {
            filename "/tftpboot/kermit.nb";
            hardware ethernet 00:80:c8:22:ae:de;
            fixed-address 192.168.35.70;
            }

    host elite {
        filename "/tftpboot/vmlinuz.xterm";
        hardware ethernet 00:00:79:80:34:c9;
        fixed-address 192.168.35.23;
            option host-name "elite";
    ___________________________________________________________________



 +o  the /etc/hosts file resolves IP numbers into host names

    ___________________________________________________________________
    #etc/hosts
    127.0.0.1       localhost    localhost.localdomain
    192.168.53.1    snoball      snoball.gundog.net
    192.168.53.23   elite        elite.gundog.net
    ___________________________________________________________________





 33..33..  TTffttppdd sseettuupp

 trivial ftp - after you have your IP number your client requests a
 kernal, this is delivered over ethernet.

 +o  Install tftpd, make sure it's active in /etc/inetd.conf, typical
    line


    ___________________________________________________________________
    tftp dgram udp wait root /usr/sbin/tcpd in.tftpd -s /tftpboot
    ___________________________________________________________________



 restart inetd, kill -HUP "process id of inetd"


 33..44..  KKeerrnneell iimmaaggee

 You must compile a kernel for the Client that includes NFS support and
 the NIC driver for that client compiled in (not modules).  Answer yes
 to _R_o_o_t _f_i_l_e _s_y_s_t_e_m _o_n _N_F_S_? and _B_O_O_T_P _s_u_p_p_o_r_t_?

 After building the kernel, run mknbi-linux from the Etherboot
 distribution on it.(the mknbi program in the netboot/linux directory)
 Install this tagged image as /tftpdir/"vmlinuz.xterm".


 see etherboot-4.2/doc/html/README-3.html

 should i put a copy of mine somewhere for download RH6.0 ne2000 NIC


 33..55..  SSeeccuurriittyy

 It's easiest to allow anybody and anything to run services and process
 on your computer, but one day you will be sorry. You restrict these by
 your /etc/hosts.deny and specifically restore rights by
 /etc/hosts.allow, indicative examples :

 ______________________________________________________________________
 #hosts.deny
 # all except those in hosts.allow
 ALL:ALL


 #hosts.allow
 #only hosts within my domain and my host at home.
 ALL:LOCAL, 192.168.53.       #<-- note:no space after :
 ______________________________________________________________________



 more security - look for more information in the ldp-howto's and if
 your using etherboot, in it's security howto.


 44..  CClliieenntt sseettuupp

 _N_e_t_w_o_r_k _l_o_a_d_e_r

 A small program that runs as a BIOS extension, can be loaded from a
 floppy, or you can burn an eprom chip and insert it on your network
 card for a totally diskless client. It handles the DHCPD query and
 TFTP loading and then transfers control to the loaded image. It uses
 TCP/IP protocols.


 There are two free implementations of TCP/IP net loaders: Etherboot
 and Netboot: Etherboot uses built-in drivers while Netboot uses Packet
 drivers.


 +o  see etherboot-4.2/doc/html/README-2.html,

 +o  I compiled the option to ask local or Network and default to local
    after 5 seconds

 +o  making a boot rom floppy, floppyload.bin was tricky to find, I
    copied it into the directory of compiled rom images

    ___________________________________________________________________
    cat floppyload.bin ne2000.lzrom > /dev/fd0
    ___________________________________________________________________



 55..  NNeettwwoorrkk ffiilleess ssyysstteemm


 The Client requests to mount /tftpboot/_<_I_P _a_d_d_r_e_s_s _o_f _c_l_i_e_n_t_> as its /
 by NFS from server. You must export this from the server,(maybe
 symlink to /tftpboot/_c_l_i_e_n_t to be safe.)

 _N_F_S is a big topic there is a HOWTO and two mini Howto's.

 first you need to create a copy of your current system under /tftpboot
 ken has written two scripts that do all your work, I called them
 makefirst and makecopy. my first client takes 20-30mb and the copy
 less. I used du -h to look for large unnecesary files.

 see etherboot-4.2/doc/html/diskless-5.html

 the following seem to me to be the critical files here


 55..11..  sseerrvveerr ssppeecciiffiicc


 ______________________________________________________________________
 #/etc/exports
 /tftpboot/elite             elite(rw,no_root_squash)
 /tftpboot/elite             gordon(rw,no_root_squash)
 /usr                        *.gundog.net(ro)
 /home                       *.gundog.net(rw)
 /mnt/cdrom                  (ro)

 run exportfs -a  to reread the exports file after
 changes /usr/sbin/exportfs --help


 #/etc/sysconfig/network
 NETWORKING=yes
 FORWARD_IPV4="no"
 HOSTNAME="snoball"         <-----------
 GATEWAYDEV=""
 GATEWAY=""


 #/etc/sysconfig/network-scripts/ifcfg-eth0
 IPADDR="192.168.53.1"            <-----------
 BOOTPROTO=none
 ______________________________________________________________________




 55..22..  cclliieenntt ssppeecciiffiicc






















 ______________________________________________________________________
 #tftpboot/elite/etc/fstab
 snoball:/tftpboot/elite    /               nfs rw  1 1
 none                    /proc proc          defaults   0 0
 snoball:/usr           /usr                 nfs     ro  1 1
 snoball:/home          /home                nfs     rw  1 1


 #tftpboot/elite/etc/sysconfig/network
 NETWORKING=yes
 FORWARD_IPV4=nomore
 HOSTNAME=elite
 GATEWAYDEV=
 GATEWAY="192.168.53.1"       <-----------


 #/tftpboot/elite/etc/sysconfig/network-scripts/ifcfg-eth0
 DEVICE=eth0
 USERCTL=yes
 ONBOOT=yes
 BOOTPROTO=none
 BROADCAST=192.168.53.255
 NETWORK=192.168.53.0
 NETMASK=255.255.255.0
 IPADDR=192.168.53.23         <-----------
 ______________________________________________________________________



 #odd fiddles #itemize> #item>fast...  #item>cp /usr/bin/xargs
 /tftpboot/client/bin/xargs #/itemize>


 66..  XX--tteerrmmiinnaall


 With no further changes your client should boot on the CLIENT pc, it
 just happens to be sharing it's files via NFS

 At this point you have a console terminal. you need to make just a few
 more changes to run X



 +o  Configuring X

    As root on client run Xconfigurator and mouseconfig,

    If this fails use XF86Setup check your RPMS dir on your CD (eg.ls
    *Setup*)


 +o  X Font Server













    ___________________________________________________________________
    #chech how xfs starts on server /etc/rc.d/init.d/xfs
      start)
        echo -n "Starting X Font Server: "
        rm -fr /tmp/.font-unix
        daemon --check xfs su xfs -c xfs -s /bin/sh
        touch /var/lock/subsys/xfs
        echo
        ;;

    #edit XF86Config for all machines
        FontPath  "tcp/snoball:7100"
    ___________________________________________________________________



 +o  Console login

    You are now set up for a console login to the client PC. You are
    using the client memory and processor, this is adequate for console
    programs and there and many or great merit, program in python,
    email with pine or browse with lynx.


    You may still start X from here, make the server changes in the
    next section, at the prompt type X -query snoball and you will get
    the login box to the server


 +o  Graphical login

    _S_e_r_v_e_r _s_e_t _u_p


    ___________________________________________________________________
    1. Make sure the client is matched by a clause in /etc/X11/xdm/Xaccess
    *   CHOOSER BROADCAST   #any indirect host can get a chooser


    2. Comment out the :0 in /etc/X11/xdm/Xservers
    #:0 local /usr/X11R6/bin/X

    3. Then make sure that xdm is run from the init scripts.
    #etc/inittab
    id:5:initdefault:

    and
    # Run xdm in runlevel 5
    # xdm is now a separate service
    x:5:respawn:/etc/X11/prefdm -nodaemon
    xdm:5:respawn:/usr/X11R6/bin/xdm -nodaemon
    ___________________________________________________________________




 _O_n _t_h_e _c_l_i_e_n_t

 Get the slow PC's to run on the server, Fast PC's (eg 166mhz 32mb
 ram)can run ok on their own CPU and memory


 the part maarked WARNING dosn't actually work as yet, but I'm close to
 getting the syntax correct, use the two stage method via the console
 login in the mean time.

 ______________________________________________________________________
 #/tftpboot/elite/etc/inittab

 id:5:initdefault:                                    #WARNING
 x:5:respawn:/usr/X11R6/bin/Xwrapper -query snoball   #WARNING

 OR to run on client ??

 id:3:initdefault:                                    #runlevel 3 ie console
 x:5:respawn:/etc/X11/prefdm -nodaemon
 ______________________________________________________________________





 77..  AAcckknnoowwlleeddggmmeennttss && ffuurrtthheerr eexxeerrcciisseess


 _M_a_r_k_u_s _G_u_t_s_c_h_k_e _a_n_d _K_e_n _Y_a_p the authors of the Etherboot program.



 Extend your system with the following programs

 +o  squid -      cache your web browsing for others on your network

 +o  junkbuster - banish web banner adds

 +o  mailman -    mailinglist ;setup via e-mail or web

 +o  imp -        web based email (with a java enabled browser)

 +o  python -     for some Java and C is just too hard

 +o  sgmltools -  knock out multiple versions of your docs

 +o  suggestions ?

 stephen7 at bigfoot.com

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