1 .TH IFCONFIG 8 "2002-07-04" "net-tools" "Linux Programmer's Manual"
3 ifconfig \- configure a network interface
5 .B "ifconfig [-v] [-a] [-s] [interface]"
7 .B "ifconfig [-v] interface [aftype] options | address ..."
10 is used to configure the kernel-resident network interfaces. It is
11 used at boot time to set up interfaces as necessary. After that, it
12 is usually only needed when debugging or when system tuning is needed.
14 If no arguments are given,
16 displays the status of the currently active interfaces. If
19 argument is given, it displays the status of the given interface
22 argument is given, it displays the status of all interfaces, even
23 those that are down. Otherwise, it configures an interface.
26 If the first argument after the interface name is recognized as
27 the name of a supported address family, that address family is
28 used for decoding and displaying all protocol addresses. Currently
29 supported address families include
45 display all interfaces which are currently available, even if down
48 display a short list (like netstat -i)
51 be more verbose for some error conditions
54 The name of the interface. This is usually a driver name followed by
55 a unit number, for example
57 for the first Ethernet interface.
60 This flag causes the interface to be activated. It is implicitly
61 specified if an address is assigned to the interface.
64 This flag causes the driver for this interface to be shut down.
67 Enable or disable the use of the ARP protocol on this interface.
72 mode of the interface. If selected, all packets on the network will
73 be received by the interface.
78 mode. If selected, all multicast packets on the network will be
79 received by the interface.
82 This parameter sets the interface metric.
85 This parameter sets the Maximum Transfer Unit (MTU) of an interface.
88 Set the remote IP address for a point-to-point link (such as
89 PPP). This keyword is now obsolete; use the
94 Set the IP network mask for this interface. This value defaults to the
95 usual class A, B or C network mask (as derived from the interface IP
96 address), but it can be set to any value.
98 .B "add addr/prefixlen"
99 Add an IPv6 address to an interface.
101 .B "del addr/prefixlen"
102 Remove an IPv6 address from an interface.
104 .B "tunnel aa.bb.cc.dd"
105 Create a new SIT (IPv6-in-IPv4) device, tunnelling to the given destination.
108 Set the interrupt line used by this device. Not all devices can
109 dynamically change their IRQ setting.
112 Set the start address in I/O space for this device.
115 Set the start address for shared memory used by this device. Only a
116 few devices need this.
119 Set the physical port or medium type to be used by the device. Not
120 all devices can change this setting, and those that can vary in what
121 values they support. Typical values for
127 (twisted-pair 10Mbps Ethernet),
129 (external transceiver) and so on. The special medium type of
131 can be used to tell the driver to auto-sense the media. Again, not
132 all drivers can do this.
134 .B "[-]broadcast [addr]"
135 If the address argument is given, set the protocol broadcast
136 address for this interface. Otherwise, set (or clear) the
138 flag for the interface.
140 .B "[-]pointopoint [addr]"
141 This keyword enables the
143 mode of an interface, meaning that it is a direct link between two
144 machines with nobody else listening on it.
146 If the address argument is also given, set the protocol address of
147 the other side of the link, just like the obsolete
149 keyword does. Otherwise, set or clear the
151 flag for the interface.
154 Set the hardware address of this interface, if the device driver
155 supports this operation. The keyword must be followed by the
156 name of the hardware class and the printable ASCII equivalent of
157 the hardware address. Hardware classes currently supported include
168 Set the multicast flag on the interface. This should not normally be needed
169 as the drivers set the flag correctly themselves.
172 The IP address to be assigned to this interface.
175 Set the length of the transmit queue of the device. It is useful to set this
176 to small values for slower devices with a high latency (modem links, ISDN)
177 to prevent fast bulk transfers from disturbing interactive traffic like
180 Since kernel release 2.2 there are no explicit interface statistics for
181 alias interfaces anymore. The statistics printed for the original address
182 are shared with all alias addresses on the same device. If you want per-address
183 statistics you should add explicit accounting
184 rules for the address using the
188 Since net-tools 1.61 ifconfig is printing byte counters with SI units. So
189 1 KiB are 2^10 byte. Note, the numbers are truncated to one decimal (which can
190 by quite a large error if you consider 0.1 PiB is 112.589.990.684.262
193 Interrupt problems with Ethernet device drivers fail with EAGAIN
194 .I (SIOCSIIFLAGS: Resource temporarily unavailable)
195 it is most likely a interrupt conflict. See
196 .I http://www.scyld.com/expert/irq-conflict.html
197 for more information.
203 .I /proc/net/if_inet6
205 While appletalk DDP and IPX addresses will be displayed they cannot be
206 altered by this command.
208 route(8), netstat(8), arp(8), rarp(8), ipchains(8)
210 http://physics.nist.gov/cuu/Units/binary.html - Prefixes for binary multiples
212 Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
214 Alan Cox, <Alan.Cox@linux.org>
216 Phil Blundell, <Philip.Blundell@pobox.com>
220 Bernd Eckenfels, <net-tools@lina.inka.de>