How to Configure a Private Network on Ubuntu

Introduction

When deploying a Vultr cloud server with a private network, you need to manually configure the private adapter. The examples shown in this guide are IPv4, but Vultr supports both IPv4 and IPv6. Vultr also supports multiple VLANs over a single private network interface with 802.1q tags. You'll find your server's information on the information page under Settings > IPv4. In the example below, the public network address is 192.0.2.123, and the private network address is 10.10.10.3. You'll find configuration samples for your server by clicking "View our networking configuration tips and examples."

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Private Networking Notes

• When you enable private networking, you may use any RFC1918 private address as long as there are no conflicts with your other instances. Valid addresses include:
  • 10.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16
• Private IP addresses in the customer portal are suggestions. You are not required to use the suggested private IP addresses.
• You can attach a maximum of 126 instances to a single private network. If you require more, please contact our engineering team.
• Private networks can not communicate between locations, regardless of IP addressing. For example, server instances in Miami can not see private networks in Dallas.
• Private networks do not have DHCP, and you must manually manage your IP address space or install a DHCP server on your private network.
• For optimal performance, set the private network adapter MTU to 1450 when configuring the NIC at the OS level.
• We also have guides to configure multiple private networks.

Ubuntu 12.xx - Ubuntu 15.xx

Verify that private networking is enabled for your cloud server. Your private network device is eth1. Your public network device is eth0.

Add the following lines to the /etc/network/interfaces file. Replace 10.10.10.3 with your IP address.

auto eth1
iface eth1 inet static
    address 10.10.10.3
    netmask 255.255.0.0
    mtu 1450

Start the interface or reboot.

ifup eth1

Ubuntu 16.xx, Ubuntu 17.04

Verify that private networking is enabled for your cloud server. Your private network device is ens7. Your public network device is ens3.

Add the following lines to the /etc/network/interfaces file. Replace 10.10.10.3 with your IP address.

auto ens7
iface ens7 inet static
    address 10.10.10.3
    netmask 255.255.0.0
    mtu 1450

Start the interface or reboot.

ifup ens7

Ubuntu 17.10 through 20.04

Verify that private networking is enabled for your cloud server. Your private network device is ens7. Your public network device is ens3.

1. Find the MAC address of the ens7 adapter.

   # ip addr
   

2. Look for the link/ether value of adapter ens7, as in the example below (00:00:00:00:00:00):

   3: ens7: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
       link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
   

3. Populate /etc/netplan/10-ens7.yaml with the following text. Replace 10.10.10.3 with your IP address, and 00:00:00:00:00:00 with your MAC address.

   network:
     version: 2
     renderer: networkd
     ethernets:
       ens7:
         match:
           macaddress: 00:00:00:00:00:00
         mtu: 1450
         dhcp4: no
         addresses: [10.10.10.3/16]
   

4. Update networking or reboot.

   # netplan apply
   

Manage Private Networks via API

The Vultr API offers several endpoints to manage private networks.