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Configuring an Additional IP block in a vRack

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As well as private IP addressing, the vRack also allows you to route public IP traffic through your server’s vRack port using a public IP address block.

Warning

Limitations:

  • IP blocks added to the vRack are limited to 5 Gbps.
  • This feature might be unavailable or limited on servers of the Eco product line.
  • Additional IP blocks purchased in the Singapore and Mumbai (YNM) data centers are not supported by vRack services.
Info

vRack supports both IPv4 and IPv6 public routing with Additional IP address blocks. You can find the instructions on how to configure IPv6 blocks in our Configuring an Additional IPv6 block in a vRack guide.

Info

This article focuses on Additional IP configuration over a vRack network. If you need guidance on Additional IP configuration with the primary IP (on the public network interface), read the following articles:

 

Requirements

  • A public block of IP addresses in your account, with a minimum of four addresses
  • Your chosen private IP address range
  • A vRack-compatible server
  • An active vRack service in your account

OVHcloud Control Panel Access

  • Direct link: vRack
  • Navigation path: Network > vRack private network

 

Instructions

Info

For example purposes, we'll be using an IP block of 46.105.135.96/28 and eth1 for the secondary network interface, which is dedicated to the vRack.

Also, the network configuration file we refer to is located in /etc/network/interfaces. The equivalent file on your server may be located somewhere else, depending on your operating system. The file content may also be different. If you encounter any difficulties, please refer to the official documentation for your distribution.

Add the IP block to the vRack

Warning

NOTE: Once an IP block is added to the vRack, it is no longer attached to a physical server.

This setup allows you to configure IPs of the same block on multiple servers, provided that these servers are all in the same vRack as the IP block. The IP block must have at least two usable IPs or more for this to be possible.

Select your vRack from the list to display the list of eligible services. Choose the IP block you wish to add to the vRack and click on the Add button.

Configure IP on vRack

 

Configure a usable IP address

Warning

NOTE: The IP blocks must be configured on the private interface.

For vRack purposes, the first, penultimate, and last addresses in any given IP block are always reserved for the network address, network gateway, and network broadcast, respectively. This means that the first usable address is the second address in the block, as shown in the example below:

46.105.135.96   Reserved: Network address
46.105.135.97   First usable IP
46.105.135.98
46.105.135.99
46.105.135.100
46.105.135.101
46.105.135.102
46.105.135.103
46.105.135.104
46.105.135.105
46.105.135.106
46.105.135.107
46.105.135.108
46.105.135.109  Last usable IP
46.105.135.110  Reserved: Network gateway
46.105.135.111  Reserved: Network broadcast

To configure the first usable IP address, we need to edit the network configuration file, as shown below. We will also need to use a subnet mask (255.255.255.240).

Info

The subnet mask we've used in our example is appropriate for our IP block. Your subnet mask may differ depending on the size of your block. When you purchase your IP block, you’ll receive an email telling you which subnet mask to use.

 

Download the iproute2 package

Before you begin, download and install iproute2, a package for manual IP routing configuration. This package may already be available on your server — if so, skip to the next step.

Establish an SSH connection to your server and run the following command from the command line. This will download and install iproute2.

sudo apt-get install iproute2

Fedora

sudo dnf install iproute

 

Configure your VM

Debian 11
CentOS, AlmaLinux, and Rocky Linux (8/9)
Ubuntu & Debian 12+
Fedora, AlmaLinux, and Rocky Linux (10)
Windows Server

Configure the Additional IP

Using a text editor of your choice, open the network configuration file located in /etc/network/interfaces.d for editing. Here, the file is called 50-cloud-init.

/etc/network/interfaces.d/50-cloud-init

auto eth1
iface eth1 inet static
address 46.105.135.97
netmask 255.255.255.240
broadcast 46.105.135.111

 

Create a new IP routing table

Next, we need to create a new IP route for the vRack. We'll be adding a new traffic rule by amending the file, as shown below:

sudo nano /etc/iproute2/rt_tables
#
# reserved values
#
255  local
254  main
253  default
0    unspec
#
# local
#
#1   inr.ruhep
1 vrack

 

Amend the network configuration file

For example purposes, the network configuration file we refer to is located in /etc/network/interfaces. The equivalent file on your server may be located somewhere else, depending on your operating system.

Finally, we need to amend the network configuration file to account for the new traffic rule and route the vRack traffic through the network gateway address of 46.105.135.110.

sudo nano /etc/network/interfaces.d/50-cloud-init

auto eth1
iface eth1 inet static
address 46.105.135.97
netmask 255.255.255.240
broadcast 46.105.135.111
post-up ip route add 46.105.135.96/28 dev eth1 table vrack
post-up ip route add default via 46.105.135.110 dev eth1 table vrack
post-up ip rule add from 46.105.135.96/28 table vrack
post-up ip rule add to 46.105.135.96/28 table vrack

Now reboot your server to apply the changes, or enable the new network interface:

ip link set eth1 up

 

Troubleshooting

If you are unable to establish a connection from your VM or server to the private network, please send us a ticket from your control panel with the following:

  • IP source and IP destination
  • Ifconfig -a or ipconfig /all from both servers or VMs (setup network configuration interface)
  • ping in both ways
  • arp -a
  • Routing table

Please, include the results from above in your ticket.

 

Go further

Browse all the Dedicated Servers guides.

Browse the rest of the OVHcloud US documentation for guides on our other products and services.

Learn more about Dedicated Servers on the OVHcloud US website.