Configure OVH proxmox server networking with additional IP

this post focus on configure the networking settings of ADVANCED GEN-2 dedicate server

intro

OVH changed fail-over IP to additional IP, we will talk about how to configure this on proxmox.

Step 1: install proxmox on a dedicate server.

I use OVH proxmox template , you can use an image to do that.

Step 2: configure master server IP.

We already got an public IP after bought the server, after installation the system, we can login through ssh or use KVM from OVH webpage.

To configure networking we need to use bridge. The configure file is like this:

# cat /etc/network/interfaces

auto lo
iface lo inet loopback

auto enp10s0f0np0 # device name, you can use command "ip a " to find out your device
iface enp10s0f0np0 inet static
        address MASTER_PUBLIC_IP/32
        gateway 100.64.0.1  # this information can be found on ovh web panel


auto vmbr0 # this is the default name of proxmox
iface vmbr0 inet static
        address 192.168.0.1/24
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        up ip route add ADDITIONAL_IP/32 dev vmbr0 # you can add more additional IPs
        up ip route add ADDITIONAL_IP2/32 dev vmbr0 # you can add more additional IPs
# route configure
        post-up iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o enp10s0f0np0 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s 192.168.0.0/24 -o enp10s0f0np0 -j MASQUERADE


iface vmbr0 inet6 static
        address IP_V6/56
        gateway fe80::1

Step 3: set network IP forward

Edit the file /etc/sysctl.conf and uncomment net.ipv4.ip_forward=1 to make it work.

Step 4: restart networking

You can use systemctl restart networking to restart network.

tips: restart your server may help you a lot when network is unreachable

Step 5: install a virtual server.

I love debian so I use it as an example.

Step 6: configure vm networking

After installed the vm server, we can login through the console from proxmox panel.

The main configure file is also /etc/network/interfaces, this is how it looks like.

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback


auto ens18 # once again, you can find your device name with command "ip a"

iface ens18 inet static
        address 192.168.0.2/24 # set an IP in the same net as master server

iface ens18 inet static
        address ADDITIONAL_IP/32 # additional ip
        up ip route replace default via 192.168.0.1 dev $IFACE onlink src ADDITIONAL_IP

Step 7: restart vm network

Command is the same: systemctl restart networking

Step 8: test

Now you can test with ping to check if network is available

ping 8.8.8.8

Once again, if anything doesnot work as expected, RESTART your dedicate server maybe help.