1IFTAB(5) Linux Programmer's Manual IFTAB(5)
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6 iftab - static information about the network interfaces
7
9 The file /etc/iftab contains descriptive information about the various
10 network interfaces. iftab is only used by the program ifrename(8) to
11 assign a consistent network interface name to each network interface.
12 /etc/iftab defines a set of mappings. Each mapping contains an inter‐
14 face name and a set of selectors. The selectors allow ifrename to iden‐
15 tify each network interface on the system. If a network interface
16 matches all descriptors of a mapping, ifrename attempt to change the
17 name of the interface to the interface name given by the mapping.
18
20 Each mapping is described on a separate line, it starts with an inter‐
21 face name, and contains a set of descriptors, separated by space or
22 tabs.
23 The relationship between descriptors of a mapping is a logical and. A
25 mapping matches a network interface only is all the descriptors match.
26 If a network interface doesn't support a specific descriptor, it won't
27 match any mappings using this descriptor.
28 If you want to use alternate descriptors for an interface name (logical
30 or), specify two different mappings with the same interface name (one
31 on each line). Ifrename always use the first matching mapping starting
32 from the end of iftab, therefore more restrictive mapping should be
33 specified last.
34
36 The first part of each mapping is an interface name. If a network
37 interface matches all descriptors of a mapping, ifrename attempt to
38 change the name of the interface to the interface name given by the
39 mapping.
40 The interface name of a mapping is either a plain interface name (such
42 as eth2 or wlan1) or a interface name pattern containing a single wild‐
43 card (such as eth* or wlan*). In case of wildcard, the kernel replace
44 the '*' with the lowest available integer making this interface name
45 unique. Note that wildcard is only supported for kernel 2.6.1 and
46 2.4.30 and later.
47 It is discouraged to try to map interfaces to default interfaces names
49 such as eth0, wlan0 or ppp0. The kernel use those as the default name
50 for any new interface, therefore most likely an interface will already
51 use this name and prevent ifrename to use it. Even if you use takeover,
52 the interface may already be up in some cases. Not using those name
53 will allow you to immediately spot unconfigured or new interfaces.
54 Good names are either totally unique and meaningfull, such as mydsl or
55 privatehub, or use larger integer, such as eth5 or wlan5. The second
56 type is usually easier to integrate in various network utilities.
57
59 Each descriptor is composed of a descriptor name and descriptor value.
60 Descriptors specify a static attribute of a network interface, the goal
61 is to uniquely identify each piece of hardware.
62 Most users will only use the mac selector, other selectors are for more
64 specialised setup.
65 mac mac address
67 Matches the MAC Address of the interface with the specified MAC
68 address. The MAC address of the interface can be shown using
69 ifconfig(8) or ip(8). The specified MAC address may contain a
70 '*' for wilcard matching.
71 This is the most common selector, as most interfaces have a
72 unique MAC address allowing to identify network interfaces with‐
73 out ambiguity. However, some interfaces don't have a valid MAC
74 address until they are brought up, in such case using this
75 selector is tricky.
76 arp arp type
78 Matches the ARP Type (also called Link Type) of the interface
79 with the specified ARP type. The ARP Type of the interface can
80 be shown using ifconfig(8) or ip(8).
81 This selector is useful when a driver create multiple network
82 interfaces for a single network card.
83 driver driver name
85 Matches the Driver Name of the interface with the specified
86 driver name. The Driver Name of the interface can be shown using
87 ethtool -i(8).
88 businfo bus information
90 Matches the Bus Information of the interface with the specified
91 bus information. The Bus Information of the interface can be
92 shown using ethtool -i(8).
93 firmware firmware revision
95 Matches the Firmware Revision of the interface with the firmware
96 revision information. The Firmware Revision of the interface can
97 be shown using ethtool -i(8).
98 baseaddress base address
100 Matches the Base Address of the interface with the specified
101 base address. The Base Address of the interface can be shown
102 using ifconfig(8).
103 Because most cards use dynamic allocation of the Base Address,
104 this selector is only useful for ISA and EISA cards.
105 irq irq line
107 Matches the IRQ Line (interrupt) of the interface with the spec‐
108 ified IRQ line. The IRQ Line of the interface can be shown using
109 ifconfig(8).
110 Because there are IRQ Lines may be shared, this selector is usu‐
111 ally not sufficient to uniquely identify an interface.
112 iwproto wireless protocol
114 Matches the Wireless Protocol of the interface with the speci‐
115 fied wireless protocol. The Wireless Protocol of the interface
116 can be shown using iwconfig(8).
117 This selector is only supported on wireless interfaces and is
118 not sufficient to uniquely identify an interface.
119 pcmciaslot pcmcia slot
121 Matches the Pcmcia Socket number of the interface with the spec‐
122 ified slot number. Pcmcia Socket number of the interface can be
123 shown using cardctl ident(8).
124 This selector is usually only supported on 16 bits cards, for 32
125 bits cards it is advised to use the selector businfo.
126 SYSFS{filename} value
128 Matches the sysfs attribute given by filename to the specified
129 value. sysfs attributes of the interface can be read in one of
130 the directory in the directory /sys/class/net/. For example,
131 the filename address is the MAC address of the device and should
132 be identical to the selector mac.
133 The sysfs filesystem is only supported with 2.6.X kernel and
134 need to be mounted. sysfs selectors are not as efficient as
135 other selectors, therefore they should be avoided for maximum
136 performance.
137
139 # This is a comment
140 eth2 mac 08:00:09:DE:82:0E
141 eth3 driver wavelan interrupt 15 baseaddress 0x390
142 eth4 driver pcnet32 businfo 0000:02:05.0
143 air* mac 00:07:0E:* arp 1
144 myvpn SYSFS{address} 00:10:83:*
145
147 Jean Tourrilhes - jt@hpl.hp.com
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150 /etc/iftab
151
153 ifrename(8), ifconfig(8), ip(8), ethtool(8), iwconfig(8).
154wireless-tools 01 March 2004 IFTAB(5)