====== Ubuntu - Networking - Configuration - Virtual Network Interfaces - Configure Temporary Virtual Network Interface ======

===== Create Temporary Virtual Network Interface =====

<code bash>
ifconfig eth0:0 192.168.1.123
</code>

<WRAP info>
**NOTE:**  This creates a new virtual network interface based on original **eth0** physical interface.

The only most important condition for creating the virtual network interface is the physical network interface, as in our case eth0 must exists.

</WRAP>


----

===== Check existing interface =====

<code bash>
ifconfig eth0
</code>

returns:

<code bash>
eth0 Link encap:Ethernet  HWaddr 3c:97:0e:02:98:c8  
inet addr:192.168.1.69  Bcast:192.168.1.255  
Mask:255.255.255.0
</code>

----

===== Ping the existing interface =====

<code bash>
ping 192.168.1.69
</code>

returns:

<code bash>
PING 192.168.1.69 (192.168.1.69) 56(84) bytes of data.
64 bytes from 192.168.1.69: icmp_seq=1 ttl=64 time=0.024 ms
64 bytes from 192.168.1.69: icmp_seq=2 ttl=64 time=0.030 ms
64 bytes from 192.168.1.69: icmp_seq=3 ttl=64 time=0.024 ms
64 bytes from 192.168.1.69: icmp_seq=4 ttl=64 time=0.026 ms
64 bytes from 192.168.1.69: icmp_seq=5 ttl=64 time=0.021 ms

--- 192.168.1.69 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4090ms
rtt min/avg/max/mdev = 0.021/0.025/0.030/0.003 ms
</code>

----

===== Configure a new virtual interface based on eth0 =====

<code>
ifconfig eth0:0
</code>

returns:

<code bash>
eth0:0    Link encap:Ethernet  HWaddr 3c:97:0e:02:98:c8  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          Interrupt:20 Memory:f1600000-f1620000 
</code>

----

===== Assign an IP Address to the virtual interface =====

<code bash>
ifconfig eth0:0 192.168.1.123
</code>

----

===== Check the virtual interface =====

<code bash>
ifconfig eth0:0
</code>

returns:

<code bash>
eth0:0    Link encap:Ethernet  HWaddr 3c:97:0e:02:98:c8  
          inet addr:192.168.1.123  Bcast:192.255.255.255  Mask:255.0.0.0
</code>

----

===== Ping the virtual interface =====

<code bash>
ping 192.168.1.123
</code>

returns:

<code bash>
PING 192.168.1.123 (192.168.1.123) 56(84) bytes of data.
64 bytes from 192.168.1.123: icmp_req=1 ttl=64 time=0.060 ms
64 bytes from 192.168.1.123: icmp_req=2 ttl=64 time=0.057 ms
</code>

----