ISC DHCP

This page explains how to install and use the ISC DHCP server.


 * Also See: DHCP and BOOTP Parameters & DNSMasq

Installing the ISC DHCP Server
First you need to install the dhcp server yum -y install dhcp

Basic DHCP Server Configuration
This is a vary basic configuration. The below configuration will allow 20 hosts to connect via the 192.168.1.0 network. They will receive a example.com hostname and be confiured to use the 192.168.1.1 gateway and nameserver(DNS). allow bootp; allow booting; default-lease-time 1080000; # The wait time before a client will start to renew, in seconds max-lease-time 288000000;   # The Maximum time a client can keep it's IP before it MUST renew, in seconds option subnet-mask 255.255.255.0; option broadcast-address 192.168.1.255; option routers 192.168.1.1; # This is your clients default gateway option domain-name-servers 192.168.1.1;  # This is your clients DNS server option domain-name "example.com";  # This is your clients domain name ddns-update-style ad-hoc; option ip-forwarding off; option nntp-server time.nist.gov; subnet 192.168.1.0 netmask 255.255.255.0 { range 192.168.1.50 192.168.1.30; } # And here is the standard static IP system setup host Samantha { hardware ethernet 00:b0:d0:db:02:bd; fixed-address 192.168.1.2; }
 * /etc/dhcpd.conf

Now lets make sure the dhcp demon is setup to auto start /sbin/chkconfig dhcpd on and to confirm it will start /sbin/chkconfig --list dhcpd If it is setup to start at boot you will see something like this: dhcpd          0:off   1:off   2:on    3:on    4:on    5:on    6:off And Start it /sbin/service dhcpd start

Advanced DHCP Server Configuration
dnssec-keygen -a HMAC-MD5 -b 128 -n HOST dnskey option time-servers 192.168.1.1; allow bootp; allow booting; allow client-updates; ddns-update-style interim; ddns-updates on; allow unknown-clients; option subnet-mask 255.255.255.0; option broadcast-address 192.168.1.255; option domain-name-servers 192.168.1.2, 192.168.1.1; option ip-forwarding off; option nntp-server time.nist.gov; option netbios-name-servers 192.168.1.3; key dnskey { algorithm hmac-md5; secret "asiomasdfeCEDDo1JTt8Q=="; }; zone example.com. { 	primary 192.168.1.1; key dnskey; } zone wireless.example.com. { 	primary 192.168.2.1; key dnskey; } zone 1.168.192.in-addr.arpa. { 	primary 192.168.1.1; key dnskey; } zone 2.168.192.in-addr.arpa. { 	primary 192.168.1.1; key dnskey; } subnet 192.168.1.0 netmask 255.255.255.0 { authoritative; allow client-updates; allow unknown-clients; option domain-name "example.com"; option routers 192.168.1.1; pool { ddns-updates on; range 192.168.1.50 192.168.1.254; } 	} subnet 192.168.2.0 netmask 255.255.255.0 { authoritative; allow client-updates; allow unknown-clients; option domain-name "wireless.example.com"; option routers 192.168.2.1; option domain-name-servers 192.168.2.1; pool { ddns-updates on; range 192.168.2.2 192.168.2.254; } 	} host computer1 { hardware ethernet 00:16:76:28:08:99; fixed-address 192.168.1.3; } host computer2 { ddns-hostname "computer2"; hardware ethernet 00:0f:cb:9f:f5:ca; fixed-address 192.168.2.4; }
 * /etc/dhcpd.conf
 * 1) Local DDNS Zone
 * 1) Zone Entry for example.com
 * 1) Zone Entry for wireless.example.com
 * 1) Local Area Network
 * 1) Wireless Network