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In debian 6.0.4 my static ip is and I want to add one more ip as virtual ip. For did I made following changes in /etc/networking/interfaces

# 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

# The primary network interface
allow-hotplug eth0
#NetworkManager#iface eth0 inet dhcp

auto eth0

    iface eth0 inet static

auto eth0:0
    iface eth0:0 inet static

And when I run command

/sbin/ifconfig -a
I get the below information

eth0      Link encap:Ethernet  HWaddr 44:87:fc:eb:b2:50  
          inet addr:  Bcast:  Mask:
          inet6 addr: fe80::4687:fcff:feeb:b250/64 Scope:Link
          RX packets:338433 errors:0 dropped:0 overruns:0 frame:0
          TX packets:238153 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:337480876 (321.8 MiB)  TX bytes:68577550 (65.4 MiB)

lo        Link encap:Local Loopback  
          inet addr:  Mask:
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:3735 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3735 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:494269 (482.6 KiB)  TX bytes:494269 (482.6 KiB)

pan0      Link encap:Ethernet  HWaddr 16:56:67:bf:36:84  
          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:0 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Mostly I get this but some time i get the virtual ip in the output. I have to make virtual ip permanent. How can i do that? Also I will assign this virtual ip ( to two machine.


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migrated from May 17 '12 at 17:19

This question came from our site for professional and enthusiast programmers.

Did you restart networking? – Sameer May 17 '12 at 17:42
there's nothing "virtual" about the ip address you're assigning. It exists on the system, and is aliased to eth0. You'll therefor have problems if you assign this to multiple machines on the same network. – JimB May 17 '12 at 20:27
@sameer yes i restarted networking – sjain May 18 '12 at 3:22

Alias/virtual interfaces are deprecated and should not be used. You should instead use iproute2 to add additional addresses to the actual interface:

iface eth0 inet static
    up ip addr add dev eth0

To check the configured IP addresses use ip addr show.

Assigning the same IP to multiple machines will cause neither to work correctly though.

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huh, just noticed that if you give a aliased device to ip addr, it just adds the address to the real device. – JimB May 17 '12 at 21:46
Yes, because aliased devices are an ifconfig hack to support multiple addresses. – mgorven May 17 '12 at 21:49

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