man interfaces:
代码： 全选
Lines beginning with the word "auto" are used to identify the physical interfaces to be brought up when ifup is run with the -a option. (This option is used by the
system boot scripts.) Physical interface names should follow the word "auto" on the same line. There can be multiple "auto" stanzas. ifup brings the named inter‐
faces up in the order listed.
代码： 全选
Stanzas defining logical interfaces start with a line consisting of the word "iface" followed by the name of the logical interface. In simple configurations without
mapping stanzas this name should simply be the name of the physical interface to which it is to be applied. (The default mapping script is, in effect, the echo com‐
mand.) The interface name is followed by the name of the address family that the interface uses. This will be "inet" for TCP/IP networking, but there is also some
support for IPX networking ("ipx"), and IPv6 networking ("inet6"). Following that is the name of the method used to configure the interface.代码： 全选
# 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
# PPPoE connection
auto provider
iface provider inet ppp
pre-up /sbin/ifconfig eth0 up
provider provider
为何man里又要求是physical?