my ifcfg-eth1 config as below
DEVICE=eth1
TYPE=Ethernet
UUID=5e4f36f8-14eb-4f0c-8fa9-3af9be3899a7
ONBOOT=no
NM_CONTROLLED=yes
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="System eth1"
HWADDR=00:0C:29:8A:A5:67
PEERDNS=yes
PEERROUTES=yes
q1) what does ONBOOT do ? I have set it to NO but i still see the interface when i do a IFCONFIG
[oracle@SJOAM network-scripts]$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0C:29:8A:A5:5D
inet addr:192.168.1.25 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe8a:a55d/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:61 errors:0 dropped:0 overruns:0 frame:0
TX packets:28 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:13496 (13.1 KiB) TX bytes:2231 (2.1 KiB)
eth1 Link encap:Ethernet HWaddr 00:0C:29:8A:A5:67
inet6 addr: fe80::20c:29ff:fe8a:a567/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:37 errors:0 dropped:0 overruns:0 frame:0
TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2412 (2.3 KiB) TX bytes:258 (258.0 b)
It is the same when i issue ifdown eth1, ifconfig still show eth1.
It is only when i issue ifconfig eth1 stop, then eth1 is totally remove from ifconfig.
q2) What is the difference between ONBOOT=no, ifdown eth1 and ifconfig eth1 down ?