How to create Multiple IP Address to Single Network interface
To create Multiple IP Address to Single Network interface
Creating multiple IP address using a single network interface is known as IP aliasing. Aliasing does not require any additional adaptors.This makes aliasing more cost effect. Procedure to create Multiple IP Address to a single interface is explained in this article.
To Assigning multiple IP’ s on a single network interface
Navigate to the path where the network configuration files are placed by utilising the following command.
[root@linuxhelp ~]# cd /etc/sysconfig/network-scripts/ [root@linuxhelp network-scripts]# ll total 224 -rw-r--r-- 5 root root 256 Jul 15 18:25 ifcfg-eth0 -rw-r--r-- 1 root root 254 Apr 9 2015 ifcfg-lo lrwxrwxrwx 1 root root 20 Mar 30 18:43 ifdown -> ../../../sbin/ifdown -rwxr-xr-x 1 root root 627 Apr 9 2015 ifdown-bnep . . . -rwxr-xr-x 1 root root 1219 Apr 9 2015 net.hotplug -rw-r--r-- 1 root root 14644 Apr 9 2015 network-functions -rw-r--r-- 1 root root 29853 Apr 9 2015 network-functions-ipv6
Check the physical adapter' s IP address through ip command.
[root@linuxhelp network-scripts]# ip a
1: lo: < LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: < BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:3f:43:a5 brd ff:ff:ff:ff:ff:ff
inet 192.168.5.182/24 brd 192.168.5.255 scope global eth0
inet6 fe80::20c:29ff:fe3f:43a5/64 scope link
valid_lft forever preferred_lft forever
Here the physical eth0 interface IP is “ 192.168.5.182” .
Lets create three virtual network interface(aliases) for eth0 as eth0:0 , eth0:1 , eth0:2 with the IP address 192.168.5.184 , 192.168.5.185 , 192.168.5.186 respectively.
[root@linuxhelp network-scripts]# cp ifcfg-eth0 ifcfg-eth0:0 [root@linuxhelp network-scripts]# cp ifcfg-eth0 ifcfg-eth0:1 [root@linuxhelp network-scripts]# cp ifcfg-eth0 ifcfg-eth0:2
Open the ifcfg-eth0:0 file and edit as follows.
[root@linuxhelp network-scripts]# vim ifcfg-eth0:0
DEVICE=eth0:0
HWADDR=00:0C:29:3F:43:A5
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.5.184
NETMASK=255.255.255.0
GATEWAY=192.168.5.1
DNS=8.8.8.8
Then open ifcfg-eth0:1 file and alter it as follows
[root@linuxhelp network-scripts]# vim ifcfg-eth0:1
DEVICE=eth0:1
HWADDR=00:0C:29:3F:43:A5
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.5.185
NETMASK=255.255.255.0
GATEWAY=192.168.5.1
DNS=8.8.8.8
Unfold the ifcfg-eth0:2 config file and edit it as follows.
[root@linuxhelp network-scripts]# vim ifcfg-eth0:2
DEVICE=eth0:2
HWADDR=00:0C:29:3F:43:A5
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.5.186
NETMASK=255.255.255.0
GATEWAY=192.168.5.1
DNS=8.8.8.8
Restart the network service.
[root@linuxhelp network-scripts]# service network restart
Shutting down interface eth0: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Determining if ip address 192.168.5.182 is already in use for device eth0...
Determining if ip address 192.168.5.184 is already in use for device eth0...
Determining if ip address 192.168.5.185 is already in use for device eth0...
Determining if ip address 192.168.5.186 is already in use for device eth0...
[ OK ]
Again check the physical adapter' s IP address using ip command.
[root@linuxhelp network-scripts]# ip a
1: lo: < LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: < BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:3f:43:a5 brd ff:ff:ff:ff:ff:ff
inet 192.168.5.182/24 brd 192.168.5.255 scope global eth0
inet 192.168.5.184/24 brd 192.168.5.255 scope global secondary eth0:0
inet 192.168.5.185/24 brd 192.168.5.255 scope global secondary eth0:1
inet 192.168.5.186/24 brd 192.168.5.255 scope global secondary eth0:2
inet6 fe80::20c:29ff:fe3f:43a5/64 scope link
valid_lft forever preferred_lft forever
Now you can check the IP’ s by pinging from other machines.
To Assign set of IP range on a single network interface
Copy and rename the physical network interface as " ifcfg-eth0-range0”
[root@linuxhelp network-scripts]# cp -p ifcfg-eth0 ifcfg-eth0-range0
Open the ifcfg-eth0-range0 file and edit as below
[root@linuxhelp network-scripts]# vim ifcfg-eth0-range0
DEVICE=eth0
HWADDR=00:0C:29:3F:43:A5
TYPE=Ethernet
UUID=9aba66e1-41ab-4f3f-8f29-5a9c188f19ab
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=static
IPADDR_START=192.168.5.184
IPADDR_END=192.168.5.186
NETMASK=255.255.255.0
DNS2=8.8.4.4
GATEWAY=192.168.5.1
DNS1=8.8.8.8
IPV6INIT=no
USERCTL=no
Restart the network service by using the following command.
[root@linuxhelp network-scripts]# service network restart
Shutting down interface eth0: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth0: Determining if ip address 192.168.5.182 is already in use for device eth0...
Determining if ip address 192.168.5.184 is already in use for device eth0...
Determining if ip address 192.168.5.185 is already in use for device eth0...
Determining if ip address 192.168.5.186 is already in use for device eth0...
[ OK ]
Then check the physical adapter' s IP address through ip command.
[root@linuxhelp network-scripts]# ifconfig -a
eth0 Link encap:Ethernet HWaddr 00:0C:29:3F:43:A5
inet addr:192.168.5.182 Bcast:192.168.5.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe3f:43a5/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:9377 errors:0 dropped:0 overruns:0 frame:0
TX packets:842 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:827629 (808.2 KiB) TX bytes:58456 (57.0 KiB)
eth0: Link encap:Ethernet HWaddr 00:0C:29:3F:43:A5
inet addr:192.168.5.184 Bcast:192.168.5.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
eth0:1 Link encap:Ethernet HWaddr 00:0C:29:3F:43:A5
inet addr:192.168.5.185 Bcast:192.168.5.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
eth0:2 Link encap:Ethernet HWaddr 00:0C:29:3F:43:A5
inet addr:192.168.5.186 Bcast:192.168.5.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
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:65536 Metric:1
RX packets:16 errors:0 dropped:0 overruns:0 frame:0
TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:960 (960.0 b) TX bytes:960 (960.0 b)
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Q
What is the purpose of creating multiple ip?
A
Assigning multiple IP addresses means creating multiple NIC’s using one single Network interface with each different name and different IP.
Q
How to enable network interface via command line?
A
use following command
#ifup "interface name" (or)
# nmcli connection up "interface name"
#ifup "interface name" (or)
# nmcli connection up "interface name"
Q
Where I can manually set network configuration in Debian based os?
A
The network configuration is located Under "/etc/network/interfaces"
Q
while performing this option "cp ifcfg-eth0 ifcfg-eth0:0" it shows permission denied
A
This needs to be executed as root user
Q
Is IP/Network configuration be managed under nmcli and nmtui?
A
yes in Centos7/RHEL 7 you can manage IP/Network configuration via nmcli and nmtui