在网络构建的过程中，我们需要建立多种服务器来进行网络的构建。这里我们就来讲解一下ubuntu下安装tftp、dhcp、nfs服务器的内容。首先我们看一下tftp服务器的建立，之后再来了解一下dhcp服务器和nfs服务器的安装。
第一步 安装tftp服务器
1 安装
root@ubuntu:/# apt-get install tftpd-hpa
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
Reading state information... 完成
下列新软件包将被安装：
tftpd-hpa
共升级了 0 个软件包，新安装了 1 个软件包，要卸载 0 个软件包，有 0 个软件未被升级。
需要下载 34.0kB 的软件包。
解压缩后会消耗掉 152kB 的额外空间。
获取：1 http://Ubuntu.cn99.com hardy/main tftpd-hpa 0.43-1.1ubuntu1 [34.0kB]
下载 34.0kB，耗时 5s (5921B/s)
正在预设定软件包 ...
选中了曾被取消选择的软件包 tftpd-hpa。
(正在读取数据库 ... 系统当前总共安装有 112536 个文件和目录。)
正在解压缩 tftpd-hpa (从 .../tftpd-hpa_0.43-1.1ubuntu1_i386.deb) ...
正在设置 tftpd-hpa (0.43-1.1ubuntu1) ...
root@ubuntu:/#
2 设置tftpd
root@ubuntu:~# nano /etc/default/tftpd-hpa
#Defaults for tftpd-hpa
RUN_DAEMON="yes"#上面这句表示启动守护进程，tftpd工作
OPTIONS="-l -s /var/lib/tftpboot"
#上面这句表示tftp客户端能取得的文件所存放的位置
3 启动服务
root@ubuntu:/# /etc/init.d/tftpd-hpa start
Starting HPA's tftpd: in.tftpd.
root@ubuntu:/# ps aux|grep tftp
root 26853 0.0 0.1 2196 288 ? Ss 17:26 0:00 /usr/sbin/in.tftpd -l -s /var/lib/tftpboot
root 26862 0.0 0.2 3180 748 pts/1 R+ 17:27 0:00 grep tftp
root@ubuntu:/#
4 查看服务是否开始工作
root@ubuntu:/# netstat -pna|grep tft
udp 0 0 0.0.0.0:69 0.0.0.0:* 26853/in.tftpd
unix 2 [ ] DGRAM 164700 26853/in.tftpd
root@ubuntu:/# #p#
第二步 安装dhcp服务器
1 服务器环境
root@ubuntu:/# uname -a
Linux ubuntu 2.6.22-14-generic #1 SMP Sun Oct 14 23:05:12 GMT 2007 i686 GNU/Linux
root@ubuntu:/#
2 安装命令
root@ubuntu:/# apt-get install dhcp3-server
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
Reading state information... 完成
dhcp3-server 已经是最新的版本了。
共升级了 0 个软件包，新安装了 0 个软件包，要卸载 0 个软件包，有 0 个软件未被升级。
3 设置dhcpd工作接口
root@ubuntu:~# nano /etc/default/dhcp3-server
# Defaults for dhcp initscript
# sourced by /etc/init.d/dhcp
# installed at /etc/default/dhcp3-server by the maintainer scripts
#
# This is a POSIX shell fragment
# On what interfaces should the DHCP server (dhcpd) serve DHCP requests?
# Separate multiple interfaces with spaces, e.g. "eth0 eth1".
# 下面这句用来定义工作接口，如果是多个就中间空格
# 比如INTERFACES="eth0 eth1 eth2"
INTERFACES="eth0"
（注*上面一行指明服务器端通过哪一块网卡提供dhcp服务）
4 主要设置
root@ubuntu:~# nano /etc/dhcp3/dhcpd.conf
# Sample configuration file for ISC dhcpd for Debian
#
# $Id: dhcpd.conf,v 1.1.1.1 2002/05/21 00:07:44 peloy Exp $
# The ddns-updates-style parameter controls whether or not the server will
# attempt to do a DNS update when a lease is confirmed. We default to the
# behavior of the version 2 packages ('none', since DHCP v2 didn't
# have support for DDNS.)
ddns-update-style none;
#下面是全局设置，这里定义的信息全dhcp服务器生效
#我一般注释掉了，下面可以分不同的子网进行设置
# option definitions common to all supported networks...
#option domain-name "apt-get.cn";
#option domain-name-servers 202.103.0.117, 202.103.24.68;
#default-lease-time 600;
#max-lease-time 7200;
# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;
# Use this to send dhcp log messages to a different log file (you also
# have to hack syslog.conf to complete the redirection).
log-facility local7;
# No service will be given on this subnet, but declaring it helps the
# DHCP server to understand the network topology.
#subnet 10.152.187.0 netmask 255.255.255.0 {
#}
# This is a very basic subnet declaration.
#subnet 10.254.239.0 netmask 255.255.255.224 {
# range 10.254.239.10 10.254.239.20;
# option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;
#}
# This declaration allows BOOTP clients to get dynamic addresses,
# which we don't really recommend.
#subnet 10.254.239.32 netmask 255.255.255.224 {
# range dynamic-bootp 10.254.239.40 10.254.239.60;
# option broadcast-address 10.254.239.31;
# option routers rtr-239-32-1.example.org;
#}
# A slightly different configuration for an internal subnet.
#subnet设置一个子网192.168.1.0/24
#range定义可以分配出去的地址为1.50到1.70
#option domain-name-servers定义dns为202.103.0.117等三个，这里注意每个之间要有个逗号
#option domain-name定义域名称
#option routers定义网关地址
#broadcast-address定义广播地址
#default-lease-time默认租约时间
#max-lease-time 最大租约时间
（注*下面这一段是生效部分，请按照实际情况修改）
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.50 192.168.1.70;
（注*上行的动态IP范围请不要与系统中已有的dhcp服务器冲突，比如无线路由器上自带的dhcp，但是也不需要把原有的关掉，只要范围不冲突就可以了，因为客户端在启动时会自动使用服务器端的dhcp所分配的地址、而不使用无线路由器上分配的）
option domain-name-servers 202.103.0.117,202.103.24.68,202.103.150.44;
option domain-name "apt-get.cn";
（注*上行的domain-name在联网系统里会起作用，所以请选择一个你肯定不会去访问的名字、即使你并不知道它是否被注册成为域名）
option routers 192.168.1.1;
option broadcast-address 192.168.1.255;
default-lease-time 864000;
max-lease-time 86400000;
filename "pxelinux.0";
（注*上面这一行是要手工加的很关键的信息，实际就是启动无盘工作站网卡的方式，而其中的pxelinux.0其实是一个文件名，下文将谈到这个文件如何生成）
}
# Hosts which require special configuration options can be listed in
# host statements. If no address is specified, the address will be
# allocated dynamically (if possible), but the host-specific information
# will still come from the host declaration.
#host passacaglia {
# hardware ethernet 0:0:c0:5d:bd:95;
# filename "vmunix.passacaglia";
# server-name "toccata.fugue.com";
#}
# Fixed IP addresses can also be specified for hosts. These addresses
# should not also be listed as being available for dynamic assignment.
# Hosts for which fixed IP addresses have been specified can boot using
# BOOTP or DHCP. Hosts for which no fixed address is specified can only
# be booted with DHCP, unless there is an address range on the subnet
# to which a BOOTP client is connected which has the dynamic-bootp flag
# set.
#host fantasia {
# hardware ethernet 08:00:07:26:c0:a5;
# fixed-address fantasia.fugue.com;
#}
# You can declare a class of clients and then do address allocation
# based on that. The example below shows a case where all clients
# in a certain class get addresses on the 10.17.224/24 subnet, and all
# other clients get addresses on the 10.0.29/24 subnet.
#class "foo" {
# match if substring (option vendor-class-identifier, 0, 4) = "SUNW";
#}
#shared-network 224-29 {
# subnet 10.17.224.0 netmask 255.255.255.0 {
# option routers rtr-224.example.org;
# }
# subnet 10.0.29.0 netmask 255.255.255.0 {
# option routers rtr-29.example.org;
# }
# pool {
# allow members of "foo";
# range 10.17.224.10 10.17.224.250;
# }
# pool {
# deny members of "foo";
# range 10.0.29.10 10.0.29.230;
# }
#}
5 启动服务器
root@ubuntu:/# /etc/init.d/dhcp3-server start
* Starting DHCP server dhcpd3 [ OK ]
root@ubuntu:/#
6 查看服务是否已经正常监听
root@ubuntu:/# netstat -aunp|grep dhcp
udp 0 0 0.0.0.0:67 0.0.0.0:* 23011/dhcpd3
已经在67号udp口上开始监听了 #p#
第三步 安装配置nfs服务器
1 安装
root@ubuntu:/# apt-get install nfs-common nfs-kernel-server nfs-client
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
Reading state information... 完成
nfs-common 已经是最新的版本了。
nfs-kernel-server 已经是最新的版本了。
注意，我选了 nfs-common 而非 nfs-client
nfs-common 已经是最新的版本了。
共升级了 0 个软件包，新安装了 0 个软件包，要卸载 0 个软件包，有 0 个软件未被升级。
2 配置
root@ubuntu:~# nano /etc/exports
# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes hostname1(rw,sync) hostname2(ro,sync)
#
# Example for NFSv4:
# /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt)
# /srv/nfs4/homes gss/krb5i(rw,sync)
/home/cache/netboot 192.168.1.0/24(rw,no_root_squash,sync)
（注*上面这一行是服务器端提供的磁盘空间的位置，可以是服务器的任一目录，建议将一个单独的磁盘分区挂在这个目录下。但是请注意：这个服务器端的/home/cache/netboot并不是将来客户端的虚拟根目录，因为在/home/cache/netboot下面将会有一个名为root的子目录，而这个/home/cache/netboot/root才是本文中的客户端的虚拟根目录，在启动完成后、实际运行过程中，工作就仅局限在/home/cache/netboot/root中了。建立root的问题下文将会讲到）
3 启动nfs或者重新加载
启动nfs
root@ubuntu:/# /etc/init.d/nfs-kernel-server start
* Exporting directories for NFS kernel daemon...
exportfs: /etc/exports [1]: Neither 'subtree_check' or 'no_subtree_check' specified for export "192.168.1.0/24:/home/cache/netboot".
Assuming default behaviour ('no_subtree_check').
NOTE: this default has changed since nfs-utils version 1.0.x
...done.
* Starting NFS kernel daemon
...done.
如果是修改了/etc/exports 配置文件，不需要重新启动nfs服务器，只需要刷新一下，命令如下
root@ubuntu:/# exportfs -r
exportfs: /etc/exports [1]: Neither 'subtree_check' or 'no_subtree_check' specified for export "192.168.1.0/24:/home/cache/netboot".
Assuming default behaviour ('no_subtree_check').
NOTE: this default has changed since nfs-utils version 1.0.x
