Summary
Goal: Create both primary and (backup) secondary DHCP and DNS services in a small home network.
Needed: one Linux server, one Windows machine and one DHCP capable router with a telnet interface.
Assumption: some programming experience.
Contra indication: not necessary when two Linux servers are available.
Alternative option: Dual DHCP DNS server, sourceforge.net/projects/dhcp-dns-server/files/.
Note: IP addresses, domain names, user names and passwords used here, do not reflect the actual setup.
Overview
My home network consists of one server running Linux, a number of wired clients running on Microsoft or Apple operating systems and an seemingly ever growing number of wireless clients running on a variety of platforms. The network infrastructure consists of a managed switch, a dual WAN router with wireless AP, a separate second wireless AP, a cable modem and a ADSL modem. The server is running both ISC DHCPD and ISC Bind providing crucial DHCP and DNS service to clients in the network.
The goal is to design the network in such a way that when the server is down (for whatever reason) Internet service to known clients is not interrupted. Specifically, known clients are still able to receive DHCP leases and resolve private domain names to IP addresses and vice versa. Obviously other services the server may provide, e.g. smb shares, are interrupted.
To achieve the stated goal it is necessary to have secondary DHCP and DNS services in case the primary services on the Linux server fail. Figure 1 outlines the design.
Figure 1 DHCP and DNS services and their backups
Read whole article for the details of the setup.
