Adding Secondary IPs

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Posted by - NA -, Last modified by Ben Galliart on 06 May 2013 02:25 PM

Please note: We recommend against adding IP addresses using your hosting control panel due to a number of possible issues this may cause. Instead, please try to use the methods indicated below.

Activating IPv4 addresses varies by operating system. Please find the section below for the operating system installed on your server and follow the directions carefully to ensure the IPs are properly configured. If your operating system is not listed here, you will need to consult your OS documentation for instructions on configuring IP aliases. We cannot provide IP configuration support for unsupported operating systems.

If you are experiencing difficulty for any reason, please open a new ticket with the IPs department, and include the information necessary to log into your server remotely. We'll be happy to assist you in adding the addresses to your server.

In the sections below, replace the bracketed text (remove the brackets) with the information provided above. The subnet mask should always be entered as 255.255.255.255 for IPv4 aliases. Using other netmasks may cause some of the addresses to be unusable or interfere with communication to other servers.

CentOS, Fedora, Red Hat Linux, and variants

Create a new file at /etc/sysconfig/network-scripts/ifcfg-eth0-range:1. If this file exists, please use the next available number after the colon (such as ifcfg-eth0-range:2).

nano /etc/sysconfig/network-scripts/ifcfg-eth0-range:1

Insert the following lines into the file:

IPADDR_START=[Start IP]
 IPADDR_END=[End IP]
 CLONENUM_START=1
 NETMASK=255.255.255.255

CLONENUM_START indicates the alias number to start with, so if you already have IP aliases on your server, you will need to increase it to the next available alias number. To find the currently active alias numbers, run the command "ifconfig | grep eth.:" which will list all current aliases in use in a form similar to "eth0:X" where "X" is the alias number. If the command does not output anything, you have no active aliases currently and can safely use the number 1.

Save the file by pressing Ctrl+X, hitting Y to confirm, and Enter to save. Now run the following command to apply the configuration:

/etc/init.d/network restart

Debian, Ubuntu, and variants

Edit the network interfaces configuration file:

nano /etc/network/interfaces

Look for your "iface eth0" line. If the previous line says "allow-hotplug eth0", change it to read "auto eth0" instead. If you leave "allow-hotplug" in the file, the interface may not come back up correctly when you reload the configuration. If "allow-hotplug" is not present, you do not need to do anything else to this part of the file.

Add the following lines at the end of the file. Replace "X" with the next unused number (starting at 0):

auto eth0:X
 iface eth0:X inet static
 address [Address]
 netmask 255.255.255.255

For each IP address in your range, insert another set of lines, incrementing the value of X. You may include as many addresses as you like.

Save the file by pressing Ctrl+X, hitting Y to confirm, and Enter to save. Now run the following command to apply the configuration:

/etc/init.d/networking restart

FreeBSD

Edit your /etc/rc.conf file.

ee /etc/rc.conf

Find a line that looks similar to:

ifconfig_fxp0="inet 1.2.3.4 netmask 255.255.255.252"

Below this line, insert the following. Substitute "fxp0" with the interface name that was in the line above:

ifconfig_fxp0_alias0="inet [Address] netmask 255.255.255.255"

You may include as many lines as you like, but for each additional line, increment the number after "alias" (such as "alias1", "alias2"). If you have 8 IPs, they should be numbered 0-7.

Now run the following command to apply the configuration:

/etc/rc.d/netif restart && /etc/rc.d/routing restart

Windows 2003

Go to Start > Control Panel > Administrative Tools > Routing and Remote Access
Right-click the entry below "Server Status" in left pane. (It should be something similar to "COMPUTERNAME (local)")
Click "Configure and Enable Routing and Remote Access" If this option is unavailable, skip to step 9.
Click "Next" to begin configuration when the dialog appears.
Select "Custom Configuration" and click "Next"
Select only "LAN routing" and click "Next"
Click "Finish"
When prompted to start the service, click "Yes"
In a few seconds, sub-items will appear below the server name in the left pane. Expand the "IP Routing" item and click on "General"
Right-click on "Local Area Connection" in the right pane and click "Properties"
Switch to the "Configuration" tab and click "Advanced..."
In the upper "IP addresses" section, click "Add..."
Add each IP that you were assigned individually, using a subnet mask of 255.255.255.255 and click "OK".
Repeat the previous step for each IP you are adding. When done, click "OK" on each dialog, including the warning dialog, if it appears.
Close the "Routing and Remote Access" window.

Windows 2008

Go to Start > Server Manager
Click "View Network Connections" in the "Server Summary"
Right click the connection to edit and select "Properties"
Select "Internet Protocol Version 4 (TCP/IPv4)" and click "Properties"
Click "Advanced..."
In the upper "IP addresses" section, click "Add..."
Add each IP that you were assigned individually, using a subnet mask of 255.255.255.255 and click "OK".
Repeat the previous step for each IP you are adding. When done, click "OK" on each dialog, including the warning dialog, if it appears.

If you have any problems with any procedures in this article, please feel free to contact support.

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Comments (1)

Ilyse Kazar

14 June 2011 01:01 PM

"WHERE DO I GET THE NEW IP ADDRESS FROM BEFORE I CAN FOLLOW THESE INSTRUCTIONS?"

Upon first purchasing the cloud server, it is assigned only one IP address. Before following the above instructions for configuring your server with the additional IP(s), you need to first visit the page for your VM in OnApp and "allocate" the IPs:

-- On the Networking tab for the VM choose the IP addresses sub-tab, and click the Allocate New IP Address Assignment button.
-- On the next page that loads, choose your existing network interface eth0 (or eth1 if you have provisioned additional physical network interfaces for internal network communications and are allocating an address for the internal network).
-- Then click on the IP Address field under "Select IP Address from IP Pool". A list will pop up showing you the available addresses. Select an address and click "Add IP Address Assignment".

Now you can follow the above instructions for creating "alias" network interfaces (as opposed to physical cards) so that your server can utilize your multiple IPs on one physical network interface.

Note that in the instructions for "CentOS, Fedora, Red Hat Linux, and variants", if you added only one additional IP address, simply replace both "[Start IP]" and "[End IP]" with the same IP number.