how to set up multiple IP addresses on my linux? [closed]

Question

I'm doing some computer network homework and I'm supposed to develop some sort of Peer to Peer file sharing software, and when I wanna test it I need to run a few (5) instances on my linux/ubuntnu 11.10 . which means each one need to has a unique IP address. I heard I can do that but I dunno how. how can I have many IP addresses on a single computer? thanks

Answer 1

It is not really clear what you are trying to do, but you can run multiple virtual machines (virtualization) on your PC to do your tests using a single machine.

If you want to have multiple IP addresses on the same physical interface, that is another thing. If this is what you want, you can do it the old way using ifconfig or the new way using ip addr add.

The old way:

$ sudo ifconfig eth0:0 your.ip.addr.ess netmask your.sub.net.mask up

The new way:

$ sudo ip addr add your.ip.addr.ess/mask.bits dev eth0

Of course, you need to replace your.ip.addr.ess with real value like 192.168.1.1 and your.sub.net.mask with something like 255.255.255.0. The mask.bits can be something like 24. You may need also to change the device name eth0. To view the IPs currently added, you can use ifconfig (old) or ip addr show (new).

Answer 2

You need to create a subinterface inorder to assign a multiple ip to the same interface (for e.g. eth0). The command for assigning suppose 2 Ip address like 10.100.10.1/24 & 10.100.10.2/24 to interface eth0 will be as follows

# ifconfig eth0 10.100.10.1 netmask 255.255.255.0 up

# ifconfig eth0:1 10.100.10.2 netmask 255.255.255.0 up

After this restart the network

service network restart

I hope this answers your question...

Answer 3

I think you should look into loopback side.

insider@localhost:/$ sudo ifconfig eth0:3 192.168.1.104 netmask 255.255.252.0
insider@localhost:/$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:26:b6:ff:69:93  
          inet addr:192.168.1.111  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::226:b6ff:feff:6993/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:17987 errors:0 dropped:0 overruns:0 frame:20557
          TX packets:18061 errors:15 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:13320368 (13.3 MB)  TX bytes:3143160 (3.1 MB)
          Interrupt:16 

eth0:2    Link encap:Ethernet  HWaddr 00:26:b6:ff:69:93  
          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:16 

eth0:3    Link encap:Ethernet  HWaddr 00:26:b6:ff:69:93  
          inet addr:192.168.1.104  Bcast:192.168.1.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:16 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:285 errors:0 dropped:0 overruns:0 frame:0
          TX packets:285 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:54727 (54.7 KB)  TX bytes:54727 (54.7 KB)