Add IP Aliases in RH or CentOS

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Add IP Aliases in RH or CentOS

Postby lik » Fri Aug 06, 2010 6:27 am

If you want to add additional IPs to the same NIC you should do the following:

1. Adding a network alias from command line in RH or CentOS Linux:
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/sbin/ifconfig lo
/sbin/ifconfig eth0 up
/sbin/ifconfig eth0
/sbin/ifconfig eth0:1
/sbin/ifconfig eth0:2

2. Configure a script to setup your network/IP aliases on boot:
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cd /etc/sysconfig/network-scripts/
cp ifcfg-eth0 ifcfg-eth0:1
cp ifcfg-eth0 ifcfg-eth0:2

Then edit ifcfg-eth0:1 and ifcfg-eth0:2 files and add your IP aliases there. For example:
cat /etc/sysconfig/network-scripts/ifcfg-eth0\:1
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3. Also in RH and CentOS Linux it is possible to add as IP aliases a range of IPs. To do that go to :
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cd /etc/sysconfig/network-scripts/

directory and create a file:
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touch ifcfg-eth0-range0

with the following content:
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* IPADDR_START is the address, from which your IP range is starting.
* IPADDR_END is the address, by which your IP range is ending.
* CLONENUM_START is the number of virtual device the first IP address will be assigned to. In the above example, applying configuration changes will make IP address to be mapped to eth0:1 virtual device. to eth0:2 etc.
You can create several ranges (ifcfg-eth0-range1, ifcfg-eth0-range2 etc.). Just take care of CLONENUM_START value for these ranges not to overlap. To apply configuration you will need to issue:
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service network restart
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Joined: Wed Dec 15, 2010 3:21 am

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