I have a Debian 7 server and a usable IP address range from xx.xx.xx.90 to 93. While working on setting up the usable addresses via /etc/network/interfaces I have the following:
# 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 static
address xx.xx.xx.90
netmask 255.255.255.248
network xx.xx.xx.88
broadcast xx.xx.xx.95
gateway xx.xx.xx.89
# Example extra IP comment
up ip addr add xx.xx.xx.91/24 dev eth0 label eth0:0
down ip addr del xx.xx.xx.91/24 dev eth0 label eth0:0
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers xx.xx.xx.xx xx.xx.xx.xx
dns-search host.xx.xx
where the 2 lines below the 'Example extra IP comment' corresponds to the new IP I want to add(will be similar for the rest of the range).
When saving the above and restarting networking via sudo ifdown eth0 && sudo ifup eth0
I get the following message:
ifdown: interface eth0 not configured
RTNETLINK answers: File exists
Failed to bring up eth0.
I don't understand why it reports that eth0 is not configured and why it is not brought up.
Any help would be greatly appreciated.
UPDATE
I used sudo ifdown --force eth0 && sudo ifup --force eth0
instead as suggested in comments by Zoredache and problem is resolved.
--force
option to ifup/ifdown because your interfaces file will have irrelevant settings.