dhcp-3.0.5-******
DHCP需要給予的是:IP 掩碼 網關 DNS
配置文件是 /etc/dhcpd.conf
軟件裝好後,這個配置文件是空的,但是系統有個參照文件在/usr/share/doc/dhcp-3.0.5/dhcpd.conf.sample中,直接把這個文件複製爲/etc/dhcpd.conf就行老,直接更改這個文件就非常和諧老。
ddns-update-style interim; none ignore client-updates; #這上面是整體配置,下面是局部配置 subnet 192.168.0.0 netmask 255.255.255.0 { # --- default gateway option routers 192.168.0.1; option subnet-mask 255.255.255.0; option nis-domain "domain.org"; option domain-name "domain.org"; option domain-name-servers 192.168.1.1; option time-offset -18000; # Eastern Standard Time # option ntp-servers 192.168.1.1; # option netbios-name-servers 192.168.1.1; # --- Selects point-to-point node (default is hybrid). Don't change this unless # -- you understand Netbios very well # option netbios-node-type 2; range dynamic-bootp 192.168.0.128 192.168.0.254; default-lease-time 21600; max-lease-time 43200; #下面是靜態IP的設置 # we want the nameserver to appear at a fixed address host ns { next-server marvin.redhat.com; hardware ethernet 12:34:56:78:AB:CD; fixed-address 207.175.42.254; } } |
ddns-update-style interim; none
(定義所支持的DNS動態更新類型,none表示不支持)
這個參數是必須的,而且必須放在第一行
ignore client-updates
忽略客戶端更新
subnet 192.168.0.0 netmask 255.255.255.0
聲明分配那個網段和掩碼
option routers
設置客戶端網關的
option subnet-mask
設置客戶端子網掩碼
option domain-name-servers
設置客戶端的DNS,多個DNS需要以,(逗號)分隔
range dynamic-bootp
設置聲明網段中具體那個範圍分配給客戶端
default-lease-time
設置IP租約時間,單位是 “妙“
max-lease-time
設置IP租約最大值
hardware ethernet
設置客戶端網卡MAC
fixed-address 207.175.42.254
這個客戶端MAC需要邦定的IP
每個設置值後面都要跟分號 “;”
當DHCP啓動起來後,在租約數據庫文件 /var/lib/dhcpd/dhcpd.leases
裏面就會有記錄,最開始是沒有記錄的
例 1:綁定多個靜態IP
聲明網段192.168.0.0
路由網關爲 0.1
DNS 0.5
www 0.4,
郵件 0.3
子網掩碼爲255.255.255.0
DHCP地址池爲 0.100 到 0.200
ddns-update-style interim;none; ignore client-updates; subnet 192.168.0.0 netmask 255.255.255.0 { # --- default gateway option routers 192.168.0.1; option subnet-mask 255.255.255.0; option nis-domain "domain.org"; option domain-name "domain.org"; option domain-name-servers 192.168.0.5; option time-offset -18000; # Eastern Standard Time # option ntp-servers 192.168.1.1; # option netbios-name-servers 192.168.1.1; # --- Selects point-to-point node (default is hybrid). Don't change this unless # -- you understand Netbios very well # option netbios-node-type 2; range dynamic-bootp 192.168.0.100 192.168.0.200; default-lease-time 21600; max-lease-time 43200; # we want the nameserver to appear at a fixed address host DNS { hardware ethernet 00:12:56:78:AB:CD; fixed-address 192.168.0.5; } host www { hardware ethernet 00:45:56:AD:22:33; fixed-address 192.168.0.4; } host mail { hardware ethernet 00:CA:56:AD:27:89; fixed-address 192.168.0.3; } } |
如果只想分配IP和掩碼,那就把其他的選項註釋掉就可以老
例 2:設置多個網段分配
比如現在主機是400臺,但是在192.168.1.0這個網段只能分配254個IP,那麼就要增加網段,就是多作用域
拓撲圖:
用DHCP服務器的兩張網卡連接兩個網段,並且配置好DHCP兩張網卡自己相應的IP地址,在配置文件中設置兩個聲明就行了
ddns-update-style interim;none; ignore client-updates; subnet 192.168.0.0 netmask 255.255.255.0 { option routers 192.168.0.1; option subnet-mask 255.255.255.0; option domain-name-servers 192.168.0.5; range dynamic-bootp 192.168.0.100 192.168.0.200; default-lease-time 21600; max-lease-time 43200; } subnet 192.168.1.0 netmask 255.255.255.0 { option routers 192.168.1.1; option subnet-mask 255.255.255.0; option domain-name-servers 192.168.1.5; range dynamic-bootp 192.168.1.100 192.168.1.200; default-lease-time 21600; max-lease-time 43200; } |
圖1
圖2
如圖1和圖2所示,
在客戶端設備和DHCP服務器不再同一廣播域內的時候,中間設備即路有器(路有功能的設備,比如路由和三層交換機)必須要能夠轉發這種廣播包,具體到cisco的設備上,則啓用ip helper-address命令,來實現這種中繼功能
ip helper-address的具體介紹看
(http://www.net130.com/CMS/Pub/special/special_dhcp/special_dhcp_cisco/2006_12_26_71053.htm)
ip helper-address是把本網段的UDP廣播轉到另一個網段的指定的機器上,而且轉發到另一個網端是以 unicast(單播)的方式進行的