2.1.2 Static IP Address

Debian Installer usually has configured the network interfaces to get its network settings from a DHCP server. However to configure our system as a network server it must have a static IP address.

Our objective is to configure the internet interface eth0 with a static IP address and also provide other information, like the gateway address.

Before change the configuration the interface must be stopped:

root@server:~# ifdown eth0

Network interface configuration is stored in the /etc/network/interfaces file:

/etc/network/interfaces

# 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
# allow-hotplug eth0
# iface eth0 inet dhcp

# Static IP address
auto eth0
iface eth0 inet static
        address 192.168.1.100
        netmask 255.255.255.0
        network 192.168.1.0
        broadcast 192.168.1.255
        gateway 192.168.1.1

DNS configuration also needs to be changed. For the moment, the DNS server for our network is the DSL or Cable router/modem, with the IP address of 192.168.1.1. DNS related configuration is stored in the “/etc/resolv.conf” file:

/etc/resolv.conf

domain localdomain
search localdomain
nameserver 192.168.1.1

Now restart the network interface to get the new configuration:

root@server:~# ifup eth0

The ifconfig command allows the user to view information about the configured network interfaces. The eth0 network interface configuration should now have the new parameters:

root@server:~# ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:84:4c:b2
          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe84:4cb2/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:32 errors:0 dropped:0 overruns:0 frame:0
          TX packets:68 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:5657 (5.5 KiB)  TX bytes:9091 (8.8 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

It should also be possible to contact Internet servers:

root@server:~# ping -c3 www.debian.org
PING www.debian.org (206.12.19.7) 56(84) bytes of data.
64 bytes from bellini.debian.org (206.12.19.7): icmp_seq=1 ttl=43 time=188 ms
64 bytes from bellini.debian.org (206.12.19.7): icmp_seq=2 ttl=43 time=190 ms
64 bytes from bellini.debian.org (206.12.19.7): icmp_seq=3 ttl=43 time=185 ms

--- www.debian.org ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2005ms
rtt min/avg/max/mdev = 185.808/188.217/190.108/1.793 ms

• Debian Reference, 5.5.5. The network interface with the static IP(http://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_network_interface_with_the_static_ip)