11 option domain-name-servers 222.88.88.88,222.85.85.85;
12
13 option time-offset -18000;
14 # Eastern Standard Time
15 # option ntp-servers 192.168.1.1;
16 # option netbios-name-servers 192.168.1.1;
12
13 option time-offset -18000;
14 # Eastern Standard Time
15 # option ntp-servers 192.168.1.1;
16 # option netbios-name-servers 192.168.1.1;
17 # --- Selects point-to-point node (default is hybrid). Don't change this unless
18 # -- you understand Netbios very well
19 # option netbios-node-type 2;
20
21 range dynamic-bootp 192.168.10.1 192.168.10.111;
range dynamic-bootp 192.168.10.113 192.168.10.253;
22 default-lease-time 21600;
23 max-lease-time 43200;
24
25 # we want the nameserver to appear at a fixed address
26 host test {
27 next-server marvin.redhat.com;
28 hardware ethernet 00:0c:29:18:30:8b; 客户端的mac地址
29 fixed-address 192.168.10.112;
30 }
31 host ns {
32 next-server marvin.redhat.com;
33 hardware ethernet 12:34:56:78:AB:CD;
34 fixed-address 202.196.64.1;
35 }
36 }
37 # DHCP Server Configuration file.
38 # see /usr/share/doc/dhcp*/dhcpd.conf.sample
-- INSERT --
[root@zzu ~]# service dhcpd restart 重新启动该服务
再次测试
查看错误时,经常查看相关的日志
/var/log/message /var/lib/dhcpd/dhcp.release
案例二:dhcp中继
原理:
DHCP中继代理原理以及使用的场合(ip包的数据部分存在一个网管作用域)
中继代理原理:
DHCP客户使用IP广播来寻找同一网段上的DHCP服务器。当服务器和客户段处在不同网段,即被路由器分割开来时,路由器是不会转发这样广播包的。因此可能需要在每个网段上设置一个DHCP服务器,虽然DHCP只消耗很小的一部分资源的,但多个 DHCP服务器,毕竟要带来管理上的不方便。DHCP中继的使用使得一个DHCP服务器同时为多个网段服务成为可能。
使用的场合:
当一个网络中的主机数目较大时,手工分配IP不仅麻烦而且容易出错。DHCP服务的出现大大方便了主机IP地址的分配。现在的企业组网时,根据实际需要来划分vlan,成了必不可
少的一个步骤。如何让一个DHCP服务器同时为多个网段提供服务,就是我们所要讨论的问题。
需求分析:
在一个企业的网络中有三个子网192.168.2.0 192.168.3.0 192.168.4.0 ,在2.0网段中有一个dhcp server ip地址为192.168.2.100,通过dhcp 中继实现该服务器能够跨子网为各个局域网进行相关服务.
示意图:
linux下DHCP SERVER 的搭建
一:同上,安装相应的包并查看相应的网络参数
[root@zzu ~]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0C:29:50:03:5E
inet addr:192.168.2.100 Bcast:192.168.2.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe50:35e/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1534 errors:0 dropped:0 overruns:0 frame:0
TX packets:991 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:141086 (137.7 KiB) TX bytes:150302 (146.7 KiB)
Interrupt:75 Base address:0x2000
[root@zzu ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 192.168.2.254 0.0.0.0 UG 0 0 0 eth0
二:修改配置文件
[root@zzu ~]# vim /etc/dhcpd.conf
1
2 ddns-update-style interim;
3 ignore client-updates;
4 shared-network mynet {
5 subnet 192.168.2.0 netmask 255.255.255.0 {
6 } 这是一个空的作用域
7 subnet 192.168.3.0 netmask 255.255.255.0 {
8 option routers 192.168.3.254;
9 option subnet-mask 255.255.255.0;
10 option domain-name "tec.com"; 技术部作用域
11 option domain-name-servers 222.88.88.88,222.85.85.85;
12 range dynamic-bootp 192.168.3.1 192.168.3.253;
13 default-lease-time 21600;
14 max-lease-time 43200;
15 }
16 subnet 192.168.4.0 netmask 255.255.255.0 {
17 option routers 192.168.4.254;
18 option subnet-mask 255.255.255.0;
19 option domain-name "mkt.com"; 市场部作用域
20 option domain-name-servers 222.88.88.88,222.85.85.85;
21 range dynamic-bootp 192.168.4.1 192.168.4.253;
22 default-lease-time 21600;
23 max-lease-time 43200;
24 }
25 }
三:测试重启dhcp服务
[root@zzu ~]# service dhcpd configtest
Syntax: OK
[root@zzu ~]# service dhcpd restart
Starting dhcpd: [ OK ]
[root@zzu ~]#
路由器的配置
一:安装 dhcp-3.0.5
编辑 /etc/sysconfig/dhcrelay
二:开启dhcp中继
[root@target ~]# service dhcrelay start
Starting dhcrelay: [ok]
[root@target ~]#
[root@target ~]# chkconfig dhcrelay on
三:开启转发功能
vim /etc/sysctl.conf
[root@zzu ~]# sysctl -p
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 4294967295
kernel.shmall = 268435456
[root@zzu ~]#
Net.ipv4.ip_forward =1 执行sysctl -p 一定要执行sysctl -p
四:路由器的网络参数
五:将xp的网卡选为vmnet3模拟tec 3.0 网段的主机测试