问题：如何使用/etc/network/interfaces文件设置网络参数，例如IP地址，子网，dhcp等吗？

答：
/etc/network/interfaces文件包含Ubuntu和Debian Linux的网络接口配置信息。
在这里配置系统如何连接到网络。

定义物理接口，例如eth0

以单词auto开头的行用于标识在使用-a选项运行ifup时要启动的物理接口。

(系统引导脚本使用此选项。)物理接口名称应在同一行上的单词auto之后。
可以有多个自动节。

ifup以列出的顺序显示命名的接口。
例如，以下示例使用IP地址192.168.1.5和网关(路由器)设置为192.168.1.254的eth0(第一个网络接口卡)：

iface eth0 inet static
address 192.168.1.5
netmask 255.255.255.0
gateway 192.168.1.254

dhcp的设置界面

要将eth0设置为dhcp，请执行：

auto eth0
iface eth0 inet dhcp

示例：如何设置接口

以下是位于/usr/share/doc/ifupdown/examples/network-interfaces的文件，将此文件用作参考(不要忘记接口手册页以获得更多帮助)：

######################################################################
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
#
# A "#" character in the very first column makes the rest of the line
# be ignored. Blank lines are ignored. Lines Jan be indented freely.
# A "\" character at the very end of the line indicates the next line
# should be treated as a continuation of the current one.
#
# The "pre-up", "up", "down" and "post-down" options are valid for all 
# interfaces, and Jan be specified multiple times. All other options
# Jan only be specified once.
#
# See the interfaces(5) manpage for information on what options are 
# available.
######################################################################

# We always want the loopback interface.
#
# auto lo
# iface lo inet loopback

# An example ethernet card setup: (broadcast and gateway are optional)
#
# auto eth0
# iface eth0 inet static
#     address 192.168.0.42
#     network 192.168.0.0
#     netmask 255.255.255.0
#     broadcast 192.168.0.255
#     gateway 192.168.0.1

# A more complicated ethernet setup, with a less common netmask, and a downright
# weird broadcast address: (the "up" lines are executed verbatim when the 
# interface is brought up, the "down" lines when it's brought down)
#
# auto eth0
# iface eth0 inet static
#     address 192.168.1.42
#     network 192.168.1.0
#     netmask 255.255.255.128
#     broadcast 192.168.1.0
#     up route add -net 192.168.1.128 netmask 255.255.255.128 gw 192.168.1.2
#     up route add default gw 192.168.1.200
#     down route del default gw 192.168.1.200
#     down route del -net 192.168.1.128 netmask 255.255.255.128 gw 192.168.1.2

# A more complicated ethernet setup with a single ethernet card with
# two interfaces.
# Note: This happens to work since ifconfig handles it that way, not because
# ifup/down handles the ':' any differently.
# Warning: There is a known bug if you do this, since the state will not
# be properly defined if you try to 'ifdown eth0' when both interfaces
# are up. The ifconfig program will not remove eth0 but it will be
# removed from the interfaces state so you will see it up until you execute:
# 'ifdown eth0:1 ; ifup eth0; ifdown eth0'
# BTW, this is "bug" #193679 (it's not really a bug, it's more of a 
# limitation)
#
# auto eth0 eth0:1
# iface eth0 inet static
#     address 192.168.0.100
#     network 192.168.0.0
#     netmask 255.255.255.0
#     broadcast 192.168.0.255
#     gateway 192.168.0.1
# iface eth0:1 inet static
#     address 192.168.0.200
#     network 192.168.0.0
#     netmask 255.255.255.0

# "pre-up" and "post-down" commands are also available. In addition, the
# exit status of these commands are checked, and if any fail, configuration
# (or deconfiguration) is aborted. So:
#
# auto eth0
# iface eth0 inet dhcp
#     pre-up [ -f /etc/network/local-network-ok ]
#
# will allow you to only have eth0 brought up when the file 
# /etc/network/local-network-ok exists.

# Two ethernet interfaces, one connected to a trusted LAN, the other to
# the untrusted Internet. If their MAC addresses get swapped (because an
# updated kernel uses a different order when probing for network cards,
# say), then they don't get brought up at all.
#
# auto eth0 eth1
# iface eth0 inet static
#     address 192.168.42.1
#     netmask 255.255.255.0
#     pre-up /path/to/check-mac-address.sh eth0 11:22:33:44:55:66
#     pre-up /usr/local/sbin/enable-masq
# iface eth1 inet dhcp
#     pre-up /path/to/check-mac-address.sh eth1 AA:BB:CC:DD:EE:FF
#     pre-up /usr/local/sbin/firewall

# Two ethernet interfaces, one connected to a trusted LAN, the other to
# the untrusted Internet, identified by MAC address rather than interface
# name:
#
# auto eth0 eth1
# mapping eth0 eth1
#     script /path/to/get-mac-address.sh
#     map 11:22:33:44:55:66 lan
#     map AA:BB:CC:DD:EE:FF internet
# iface lan inet static
#     address 192.168.42.1
#     netmask 255.255.255.0
#     pre-up /usr/local/sbin/enable-masq $IFACE
# iface internet inet dhcp
#     pre-up /usr/local/sbin/firewall $IFACE

# A PCMCIA interface for a laptop that is used in different locations:
# (note the lack of an "auto" line for any of these)
#
# mapping eth0
#    script /path/to/pcmcia-compat.sh
#    map home,*,*,*                  home
#    map work,*,*,00:11:22:33:44:55  work-wireless
#    map work,*,*,01:12:23:34:45:50  work-static
#
# iface home inet dhcp
# iface work-wireless bootp
# iface work-static static
#     address 10.15.43.23
#     netmask 255.255.255.0
#     gateway 10.15.43.1
#
# Note, this won't work unless you specifically change the file
# /etc/pcmcia/network to look more like:
#
#     if [ -r ./shared ] ; then . ./shared ; else . /etc/pcmcia/shared ; fi
#     get_info $DEVICE
#     case "$ACTION" in
#         'start')
#             /sbin/ifup $DEVICE
#             ;;
#         'stop')
#             /sbin/ifdown $DEVICE
#             ;;
#     esac
#     exit 0

# An alternate way of doing the same thing: (in this case identifying
# where the laptop is is done by configuring the interface as various
# options, and seeing if a computer that is known to be on each particular
# network will respond to pings. The various numbers here need to be chosen
# with a great deal of care.)
#
# mapping eth0
#    script /path/to/ping-places.sh
#    map 192.168.42.254/24 192.168.42.1 home
#    map 10.15.43.254/24 10.15.43.1 work-wireless
#    map 10.15.43.23/24 10.15.43.1 work-static
#
# iface home inet dhcp
# iface work-wireless bootp
# iface work-static static
#     address 10.15.43.23
#     netmask 255.255.255.0
#     gateway 10.15.43.1
#
# Note that the ping-places script requires the iproute package installed,
# and the same changes to /etc/pcmcia/network are required for this as for
# the previous example.

# Set up an interface to read all the traffic on the network. This 
# configuration can be useful to setup Network Intrusion Detection
# sensors in 'stealth'-type configuration. This prevents the NIDS
# system to be a direct target in a hostile network since they have
# no IP address on the network. Notice, however, that there have been
# known bugs over time in sensors part of NIDS (for example see 
# DSA-297 related to Snort) and remote buffer overflows might even be
# triggered by network packet processing.
# 
# auto eth0
# iface eth0 inet manual
# 	up ifconfig $IFACE 0.0.0.0 up
#       up ip link set $IFACE promisc on
#       down ip link set $IFACE promisc off
#       down ifconfig $IFACE down

# Set up an interface which will not be allocated an IP address by
# ifupdown but will be configured through external programs. This
# can be useful to setup interfaces configured through other programs,
# like, for example, PPPOE scripts.
#
# auto eth0
# iface eth0 inet manual
#       up ifconfig $IFACE 0.0.0.0 up
#       up /usr/local/bin/myconfigscript
#       down ifconfig $IFACE down