DHCP Server Installation 24.04LTS

We will now set up a DHCP Server and configure it to hand out a specific range of addresses and update DNS (once we set it up)

Install the DHCP server package.

sudo apt install isc-dhcp-server

It will fail on startup as it is not configured yet.

systemctl stop isc-dhcp-server.service

Configure the interface to listen on

nano /etc/default/isc-dhcp-server

Change the parameter for "interfaces"

# On what interfaces should the DHCP server (dhcpd) serve DHCP requests?
#       Separate multiple interfaces with spaces, e.g. "eth0 eth1".
INTERFACESv4="br0"
INTERFACESv6=""

Configure / copy keys for Dynamic DNS updates and set permissions

cp /etc/bind/rndc.key /etc/dhcp/ddns-keys
chown root:root /etc/dhcp/ddns-keys/rndc.key
chmod 640 /etc/dhcp/ddns-keys/rndc.key

Configure /etc/dhcp/dhcpd.conf

nano /etc/dhcp/dhcpd.conf

The following sample config file sets up the following parameters.

• Hands out IP addresses in the range 10.3.100.1 10.3.100.200;
• Set a lease time of 8hours
• Sets the following clients default settings
  • default router = 10.3.1.1
  • domain-name-servers 10.3.200.1;
  • domain-name "scottworld.net";
  • routers 10.3.1.1;
  • broadcast-address 10.3.255.255;
  • It reserves a number of addresses by mac address for certain devices / hosts.

Its will also attempt to dynamically update DNS with new clients. (When we configure it)

# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#
# Attention: If /etc/ltsp/dhcpd.conf exists, that will be used as
# configuration file instead of this file.
#

# option definitions common to all supported networks...
option domain-name "scottworld.net";
option domain-name-servers 10.3.200.1;

default-lease-time 28800;
max-lease-time 86400;

# 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 standard;
include "/etc/dhcp/ddns-keys/rndc.key";

# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
authoritative;

# Definition of RFC 4833 Timezone Options

option tz-posix-string code 100 = string;
option tz-database-string code 101 = string;

# Global options

option domain-name "scottworld.net";
option domain-name-servers 10.3.200.1;
option ntp-servers 10.3.200.1;
option time-servers 10.3.200.1;
option time-offset 0;
option tz-posix-string "GMT0BST,M3.5.0/01:00,M10.5.0/01:00";
option tz-database-string "Europe/London";

# Dynamic DNS zones

zone scottworld.net. {
    primary 10.3.200.1;
    key rndc-key;
}

zone 3.10.in-addr.arpa. {
    primary 10.3.200.1;
    key rndc-key;
}

# Address scopes

subnet 10.3.0.0 netmask 255.255.0.0 {
    range 10.3.100.1 10.3.100.200;
    option routers 10.3.1.1;

    ddns-updates on;
    ddns-domainname "scottworld.net.";
    ddns-rev-domainname "in-addr.arpa.";
}

# ------------  Network (10.3.1.x) --------------------
host WAPLoft {
  hardware ethernet 98:9b:cb:24:e1:dd;
  fixed-address 10.3.1.2;
}
host WAPLounge {
  hardware ethernet 2c:3a:fd:23:b0:1d;
  fixed-address 10.3.1.3;
}

# ------------  Servers (10.3.200.x) --------------------

host mars {
  hardware ethernet DC:A6:32:19:ED:C1;
  fixed-address 10.3.200.2;
}
host comet {
  hardware ethernet 1c:c1:de:33:00:48;
  fixed-address 10.3.200.3;
}

# ------------  IOT (10.3.50.x) --------------------

host ddhomerun {
  hardware ethernet 00:18:DD:23:17:4F;
  fixed-address 10.3.50.1;
}
host envoy {
  hardware ethernet 00:1d:c0:73:eB:32;
  fixed-address 10.3.50.2;
}
host scottscreen {
  hardware ethernet 78:5d:c8:E3:4d:f7;
  fixed-address 10.3.50.3;
}
host Lounge-main {
  hardware ethernet 80:64:6f:8f:2e:be;
  fixed-address 10.3.50.4;
}
host Dining-main {
  hardware ethernet E8:68:E7:44:B2:EF;
  fixed-address 10.3.50.5;
}
host patio {
  hardware ethernet 2C:F4:32:B8:01:9D;
  fixed-address 10.3.50.6;
}
host porch {
  hardware ethernet 70:03:9F:6B:29:12;
  fixed-address 10.3.50.7;
}
host yamaha {
  hardware ethernet BC:30:D9:61:AD:CF;
  fixed-address 10.3.50.8;
}
host roku {
  hardware ethernet 08:05:81:2E:42:D4;
  fixed-address 10.3.50.9;
}
host Landing-main {
  hardware ethernet 70:03:9F:5C:59:36;
  fixed-address 10.3.50.10;
}
host amazon-c01e642c8 {
  hardware ethernet 3C:5C:C4:B4:32:80;
  fixed-address 10.3.50.12;
}
host amazon-5f60112a9 {
  hardware ethernet 1C:4D:66:32:FA:D9;
  fixed-address 10.3.50.13;
}
host Chromecast {
  hardware ethernet A4:77:33:B6:6F:7A;
  fixed-address 10.3.50.14;
}
host Lounge-larry {
  hardware ethernet D8:F1:5B:FB:31:73;
  fixed-address 10.3.50.15;
}
host Lounge-floor {
  hardware ethernet D8:F1:5B:FB:31:78;
  fixed-address 10.3.50.16;
}
host Dining-uplighter2 {
  hardware ethernet D8:F1:5B:FB:31:6C;
  fixed-address 10.3.50.18;
}
host PowerCord1 {
  hardware ethernet D8:F1:5B:FB:31:7C;
  fixed-address 10.3.50.19;
}
host mame {
  hardware ethernet d8:f1:5b:fb:31:8b;
  fixed-address 10.3.50.20;
}
host Lounge-colin {
  hardware ethernet d8:f1:5b:fb:31:80;
  fixed-address 10.3.50.21;
}
host Dining-uplighter1 {
  hardware ethernet d8:f1:5b:fb:32:21;
  fixed-address 10.3.50.22;
}
host MiniR2 {
  hardware ethernet 80:64:6f:8f:84:13;
  fixed-address 10.3.50.23;
}

host cyd {
  hardware ethernet e0:5a:1b:e3:52:68;
  fixed-address 10.3.50.24;
}

host FrontCam {
  hardware ethernet ec:71:db:01:b9:70;
  fixed-address 10.3.50.30;
}
host BackCam {
  hardware ethernet ec:71:db:25:f2:09;
  fixed-address 10.3.50.31;
}
host DoorBell {
  hardware ethernet 38:e7:c0:c3:61:56;
  fixed-address 10.3.50.32;
}

#host HotWaterRelay {
#  hardware ethernet d8:f1:5b:fb:32:1b;
#  fixed-address 10.3.50.33;
#}

host ipPhone {
  hardware ethernet c0:74:ad:5e:62:e4;
  fixed-address 10.3.50.40;
}


# ------------  PCs (10.3.101.x) --------------------
host mimas {
  hardware ethernet FC:AA:14:E2:72:21;
  fixed-address 10.3.101.3;
}
host printer {
  hardware ethernet 18:60:24:53:13:ED;
  fixed-address 10.3.101.100;
}
host asteroid {
  hardware ethernet 52:54:00:96:47:a8;
  fixed-address 10.3.101.2;
}
host saturn {
  hardware ethernet 74:56:3c:41:29:98;
  fixed-address 10.3.101.1;
}

Restart DHCP server and test

systemctl restart isc-dhcp-server.service