[CentOS] Network interface status

Thu Mar 21 09:21:16 UTC 2013
isdtor <isdtor at gmail.com>

Under CentOS6, is it possible to get an interface to RUNNING state
without assigning a (dummy) IP address?

# ifconfig em2
em2       Link encap:Ethernet  HWaddr 78:2B:CB:67:3E:5C
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

This was working fine on RHEL3 simply by running ifconfig up.

# ifconfig eth1 up
# ifconfig eth1
eth1      Link encap:Ethernet  HWaddr 00:11:25:57:8B:2D
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10658057 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1169901971 (1115.7 Mb)  TX bytes:0 (0.0 b)
          Base address:0x3400 Memory:d0240000-d0260000

# dmesg |grep eth1
...
e1000: eth1: e1000_watchdog: NIC Link is Up 1000 Mbps Full Duplex
#

provided there is a link.