如何使用linux ifconfig命令配置网卡

来源：  作者：Crystal

   

    About ifconfig

    The "ifconfig" command allows the operating system to setupnetwork interfaces and allow the user to view information about theconfigured network interfaces.

    Syntax

    ifconfig [-L] [-m] interface [create] [address_family] [address[/prefixlength] [dest_address]] [parameters]

    ifconfig interface destroy

    ifconfig -a [-L] [-d] [-m] [-u] [address_family]

    ifconfig -l [-d] [-u] [address_family]

    ifconfig [-L] [-d] [-m] [-u] [-C]

    address For the DARPA-Internet family, the address is either ahost name present in the host name data base, or a DARPA Internetaddress expressed in the Internet standard ``dot notation''.

    It is also possible to use the CIDR notation (also known as theslash notation) to include the netmask. That is, one can specify anaddress like 192.168.0.1/16.

    addres_family Specify the address family which affectsinterpretation of the remaining parameters. Since an interface canreceive transmissions in differing protocols with different namingschemes, specifying the address family is recommended. The address orprotocol families currently supported are ``inet'', ``inet6'',

    dest_address Specify the address of the correspondent on the other end of a point to point link.

    interface This parameter is a string of the form ``name unit'', for example, ``en0''.

    add Another name for the alias parameter. Introduced for compatibility with BSD/OS.

    alias Establish an additional network address for thisinterface. This is sometimes useful when changing network numbers, andone wishes to accept packets addressed to the old interface. If theaddress is on the same subnet as the first network address for thisinterface, a netmask of 0xffffffff has to be specified.

    -alias Remove the network address specified. This would be usedif you incorrectly specified an alias, or it was no longer needed. Ifyou have incorrectly set an NS address having the side effect ofspecifying the host portion, removing all NS addresses will allow youto respecify the host portion.

    anycast (Inet6 only.) Specify that the address configured is ananycast address. Based on the current specification, only routers mayconfigure anycast addresses. Anycast address will not be used as sourceaddress of any of outgoing IPv6 packets.

    arp Enable the use of the Address Resolution Protocol in mappingbetween network level addresses and link level addresses (default).This is currently implemented for mapping between DARPA Internetaddresses and IEEE 802 48-bit MAC addresses (Ethernet, FDDI, and TokenRing addresses).

    -arp Disable the use of the Address Resolution Protocol

    broadcast (Inet only.) Specify the address to use to representbroadcasts to the network. The default broadcast address is the addresswith a host part of all 1's.

    debug Enable driver dependent debugging code; usually, this turns on extra console error logging.

    -debug Disable driver dependent debugging code.

　　Linux下网卡命名规律：eth0，eth1.第一块以太网卡，第二块。lo为环回接口，它的IP地址固定为127.0.0.1，掩码8位。它代表你的机器本身。
　
　　1、ifconfig是查看网卡的信息。
　
　　ifconfig [Interface]
　
　　Interface是可选项，如果不加此项，则显示系统中所有网卡的信息。如果添加此选项则显示所指定的网卡信息
　
　　例如：ifconfig eth0
　

eth0 Link encap:Ethernet
HWaddr 00:0C:29:F3:3B:F2
inet addr:192.168.0.10 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:78 errors:0 dropped:0 overruns:0 frame:0
TX packets:104 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100 
RX bytes:11679 (11.4 Kb)
TX bytes:14077 (13.7 Kb)
Interrupt:10 Base address:0x1080

　
　　我们可以看到
　
　　第一行：连接类型：Ethernet（以太网）HWaddr（硬件mac地址）
　
　　第二行：网卡的IP地址、子网、掩码
　
　　第三行：UP（代表网卡开启状态）RUNNING（代表网卡的网线被接上）MULTICAST（支持组播）MTU：1500（最大传输单元）：1500字节
　
　　第四、五行：接收、发送数据包情况统计
　
　　第七行：接收、发送数据字节数统计信息。
　
　　2、ifconfig 配置网卡
　
　　配置网卡的IP地址
　
　　ifconfig eth0 192.168.0.1 netmask 255.255.255.0
　
　　在eth0上配置上192.168.0.1 的IP地址及24位掩码。若想再在eth0上在配置一个192.168.1.1/24 的IP地址怎么办？用下面的命令
　
　　ifconfig eth0：0 192.168.1.1 netmask 255.255.255.0
　
　　这时再用ifconifg命令查看，就可以看到两个网卡的信息了，分别为：eth0和eth0：0.若还想再增加IP，那网卡的命名就接着是：eth0：1、eth0：2……想要几个就填几个。ok！
　

    delete Another name for the -alias parameter.

    down Mark an interface ``down''. Whenan interface is marked ``down'', the system will not attempt totransmit messages through that interface. If possible, the interfacewill be reset to disable reception as well. This action does notautomatically disable routes using the interface.

    ether Another name for the lladdr parameter.

    lladdr addr Set the link-level addresson an interface. This can be used to e.g. set a new MAC address on anethernet interface, though the mechanism used is not ethernet-specific.The address addr is specified as a series of colon-separated hexdigits. If the interface is already up when this option is used, itwill be briefly brought down and then brought backup again in order toensure that the receive filter in the underlying ethernet hardware isproperly reprogrammed.

    media type If the driver supports themedia selection system, set the media type of the interface to type.Some interfaces support the mutually exclusive use of one of severaldifferent physical media connectors. For example, a 10Mb/s Ethernetinterface might support the use of either AUI or twisted pairconnectors. Setting the media type to ``10base5/AUI'' would change thecurrently active connector to the AUI port. Setting it to``10baseT/UTP'' would activate twisted pair. Refer to the interfaces'driver specific documentation or man page for a complete list of theavailable types.

    -mediaopt opts If the driver supportsthe media selection system, set the specified media options on theinterface. The opts argument is a comma delimited list of options toapply to the interface. Refer to the interfaces' driver specific manpage for a complete list of available options.

    tunnel src_addr dest_addr (IP tunneldevices only.) Configure the physical source and destination addressfor IP tunnel interfaces. The arguments src_addr and dest_addr areinterpreted as the outer source/destination for the encapsulatingIPv4/IPv6 header.

    deletetunnel Unconfigure the physicalsource and destination address for IP tunnel interfaces previouslyconfigured with tunnel.

    create Create the specified networkpseudo-device. If the interface is given without a unit number, try tocreate a new device with an arbitrary unit number. If creation of anarbitrary device is successful, the new device name is printed tostandard output.

    destroy Destroy the specified network pseudo-device.

　　配置网卡的硬件地址
　
　　ifconfig eth0 hw ether xx：xx：xx：xx：xx：xx
　
　　就将网卡的硬件地址更改了，此时你就可以骗过局域网内的IP地址邦定了。
　
　　将网卡禁用
　
　　ifconfig eth0 down
　
　　将网卡启用
　
　　ifconfig eth0 up
　
　　ifconfig 命令的功能很强大，还可以设置网卡的MTU，混杂模式等。就不一一介绍了，用时间可以自己研究一下。
　
　　注意：用ifconfig命令配置的网卡信息，在网卡重启后机器重启后，配置就不存在。要想将上述的配置信息永远的存的电脑里，那就要修改网卡的配置文件了。
　

    plumb Another name for the create parameter. Included for Solaris compatibility.

    unplumb Another name for the destroy parameter. Included for Solaris compatibility.

    metric n Set the routing metric of theinterface to n, default 0. The routing metric is used by the routingprotocol. Higher metrics have the effect of making a route lessfavorable; metrics are counted as addition hops to the destinationnetwork or host.

    mtu n Set the maximum transmissionunit of the interface to n, default is interface specific. The MTU isused to limit the size of packets that are transmitted on an interface.Not all interfaces support setting the MTU, and some interfaces haverange restrictions.

    netmask mask (Inet only.) Specify howmuch of the address to reserve for subdividing networks intosubnetworks. The mask includes the network part of the local addressand the subnet part, which is taken from the host field of the address.The mask can be specified as a single hexadecimal number with a leading`0x', with a dot-notation Internet address, or with a pseudo-networkname listed in the network table. The mask contains 1's for the bitpositions in the 32-bit address which are to be used for the networkand subnet parts, and 0's for the host part. The mask should contain atleast the standard network portion, and the subnet field should becontiguous with the network portion. The netmask can also be specifiedin CIDR notation after the address. See the address option above formore information.

    prefixlen len (Inet6 only.) Specifythat len bits are reserved for subdividing networks into sub-networks.The len must be integer, and for syntactical reason it must be between0 to 128. It is almost always 64 under the current IPv6 assignmentrule. If the parameter is omitted, 64 is used.

    remove Another name for the -alias parameter. Introduced for compatibility with BSD/OS.

    link[0-2] Enable special processing ofthe link level of the interface. These three options are interfacespecific in actual effect, how- ever, they are in general used toselect special modes of operation. An example of this is to enable SLIPcompression, or to select the connector type for some Ethernet cards.Refer to the man page for the specific driver for more information.

    -link[0-2] Disable special processing at the link level with the specified interface.

    up Mark an interface ``up''. This maybe used to enable an interface after an ``ifconfig down''. It happensautomatically when setting the first address on an interface. If theinterface was reset when previously marked down, the hardware will bere-initialized.

    Examples

    ifconfig eth0

    View the network settings on the first Ethernet adapter installed in the computer.

    ifconfig -a

    Display into on all network interfaces on server, active or inactive.

    ifconfig eth0 down

    If eth0 exists would take it down causing it cannot send or receive any information.

    ifconfig eth0 up

    If eth0 exists and in the down state would return it back to the up state allowing to to send and receive information.

    ifconfig eth0 192.168.1.102 netmask 255.255.255.0 broadcast 192.168.1.255

    Assign eth0 with the above values for IP, netmask and broadcast address.