Debian Router - Dhcp Server Setup
We've learned previously how to set up unbound dns server as caching dns server for our LAN users, in this article we'll configure dhcp server from which a unique ip address for each client assigned as a bonus automatically configure dns server settings for them.
In this debian router articles series also:
- Introduction.
- Hardware Requirements.
- Software installation.
- Basic Setup.
- /etc/network/Interfaces Configuration.
- Unbound dns server setup.
- DHCP server setup. (We are Here!)
- Squid setup.
- Final step iptables and sysctl.conf configuration.
We need to tell isc-dhcp-server where to listen and serve dhcp request, to do that we modify /etc/default/isc-dhcp-server as follows:
Our LAN is on eth1 so set
INTERFACESv4="eth1"
the whole file will look like:
# Defaults for isc-dhcp-server (sourced by /etc/init.d/isc-dhcp-server) # Path to dhcpd's config file (default: /etc/dhcp/dhcpd.conf). #DHCPDv4_CONF=/etc/dhcp/dhcpd.conf #DHCPDv6_CONF=/etc/dhcp/dhcpd6.conf # Path to dhcpd's PID file (default: /var/run/dhcpd.pid). #DHCPDv4_PID=/var/run/dhcpd.pid #DHCPDv6_PID=/var/run/dhcpd6.pid # Additional options to start dhcpd with. # Don't use options -cf or -pf here; use DHCPD_CONF/ DHCPD_PID instead #OPTIONS="" # On what interfaces should the DHCP server (dhcpd) serve DHCP requests? # Separate multiple interfaces with spaces, e.g. "eth0 eth1". INTERFACESv4="eth1" INTERFACESv6=""
Next edit /etc/dhcp/dhcpd.conf
Tell dhcp server that we rely on it to configure our LAN, so uncomment or add:
authoritative;
The following LAN setup support upto 248 clients/users
######################
# internal network
######################
subnet 10.5.5.0 netmask 255.255.255.0 {
range 10.5.5.6 10.5.5.254;
option domain-name-servers 10.5.5.1;
option routers 10.5.5.1;
option broadcast-address 10.5.5.255;
default-lease-time 600;
max-lease-time 7200;
}
Give LAN-AP a fixed ip address, this address must not be available for dynamiclly assigned ip addresses range, notice that we've already chosen 10.5.5.5 which is out of the range [10.5.5.6 - 10.5.5.254]
replace 00:00:00:00:00:00 with your LAN-AP mac address:
# LAN-AP need fixed ip address 10.5.5.5
# 00:00:00:00:00:00 mustbe replaces with router hardware mac address
host router{
hardware ethernet 00:00:00:00:00:00;
fixed-address 10.5.5.5;
}
The whole /etc/dhcp/dhcpd.conf will look like the following (comments strip for brevity):
# 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;
# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
authoritative;
######################
# internal network
######################
subnet 10.5.5.0 netmask 255.255.255.0 {
range 10.5.5.6 10.5.5.254;
option domain-name-servers 10.5.5.1;
option routers 10.5.5.1;
option broadcast-address 10.5.5.255;
default-lease-time 600;
max-lease-time 7200;
}
# LAN-AP need fixed ip address 10.5.5.5
# 00:00:00:00:00:00 mustbe replaces with router hardware mac address
host router{
hardware ethernet 00:00:00:00:00:00;
fixed-address 10.5.5.5;
}
Next Squid setup