Add a DNS and DHCP server with dnsmasq

In order to better control the allocation of addresses to the various bits that are now on the local network, I've added a DNS and DHCP server to 'fileserver' with dnsmasq. First install it

fileserver:~# apt-get install dnsmasq

then edit the configuration file /etc/dnsmasq -

# Don't use /etc/resolv.conf or any other
# file, get servers from this file instead
no-resolv
server=192.168.2.1

#This is our home network domain name
domain=ourhouse.net

#Don't forward anything without a full domain name
domain-needed
#Don't try to do reverse lookups of private IP addresses
bogus-priv
#Don't forward these local domains
local=/ourhouse.net/
local=/azea.net/

#Start the DHCP server
dhcp-range=192.168.2.20,192.168.2.49,12h

# Override the default route supplied by dnsmasq, which assumes the
# router is the same machine as the one running dnsmasq.
dhcp-option=3,192.168.2.1

# For debugging purposes, log each DNS query as it passes through
# dnsmasq.
log-queries

'fileserver' itself will have to have a static IP address now - since I will be turning off the DHCP server on the gateway router - therefore need to edit /etc/network/interfaces compared to the one used in the earlier post -

#This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
    address 0.0.0.0

auto br0
iface br0 inet static
    address 192.168.2.18
    netmask 255.255.255.0       
    gateway 192.168.2.1
    bridge_ports eth0 tap0
    pre-up openvpn --mktun --dev tap0
    post-down openvpn --rmtun --dev tap0

/etc/resolv.conf must be edited to make dns lookups originating on 'fileserver' use the local DNS server -

nameserver 127.0.0.1

and /etc/hosts edited so that dns lookups will find the correct addresses for 'fileserver' and 'gateway' - the only devices on the network that will not get their addresses from the new DHCP server -

127.0.0.1       localhost
192.168.2.1     gateway
192.168.2.18    fileserver

dnsmasq writes it's DHCP lease in formation to /var/lib/misc/dnsmasq.leases -

1225776083 00:0e:a6:9f:04:e7 192.168.2.32 Playroom-Router 01:00:0e:a6:9f:04:e7
1225772336 00:1a:73:bf:97:0c 192.168.2.25 AndrewsPC 01:00:1a:73:bf:97:0c
1225748001 00:10:60:a1:3c:79 192.168.2.15 Will-PC 01:00:10:60:a1:3c:79

Now I can let all other devices get there IP addresses via DHCP and I can refer to them by their hostnames - for example pinging 'fileserver' from a Windows machine gives -

C:\Documents and Settings\andrew>ping fileserver

Pinging fileserver.ourhouse.net [192.168.2.18] with 32 bytes of data:

Reply from 192.168.2.18: bytes=32 time=1ms TTL=64
Reply from 192.168.2.18: bytes=32 time=2ms TTL=64
Reply from 192.168.2.18: bytes=32 time=3ms TTL=64
Reply from 192.168.2.18: bytes=32 time=3ms TTL=64

Ping statistics for 192.168.2.18:
     Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
     Minimum = 1ms, Maximum = 3ms, Average = 2ms

and similarly pinging 'Playroom-Router' from a linux box -

box:~# ping Playroom-Router
PING Playroom-Router (192.168.2.32) 56(84) bytes of data.
64 bytes from Playroom-Router.ourhouse.net (192.168.2.32): icmp_seq=1 ttl=64 time=17.9 ms
64 bytes from Playroom-Router.ourhouse.net (192.168.2.32): icmp_seq=2 ttl=64 time=4.20 ms
64 bytes from Playroom-Router.ourhouse.net (192.168.2.32): icmp_seq=3 ttl=64 time=3.11 ms
64 bytes from Playroom-Router.ourhouse.net (192.168.2.32): icmp_seq=4 ttl=64 time=2.19 ms
64 bytes from Playroom-Router.ourhouse.net (192.168.2.32): icmp_seq=5 ttl=64 time=3.22 ms

--- Playroom-Router ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4039ms
rtt min/avg/max/mdev = 2.199/6.137/17.943/5.937 ms

Super!