To set up a TransIP BladeVPS Ubuntu 18.0.4 Private Network you need to do quite a bit of work as you do setting up the TransIP Ubuntu server itself.

Netplan Configuration

You need to do a configuration change to be loaded by netplan used by Ubuntu 17.04 up to configure networks. Do a:

sudo nano /etc/netplan/01-netcfg.yaml

and then adjust the file. In the file you will see:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    ens3:
      dhcp4: yes
      dhcp6: yes

whereas a Digital Ocean Ubuntu Droplet will already have this:

# This file is generated from information provided by
# the datasource.  Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    ethernets:
        eth0:
            addresses:
            - xxx.xxx.xxx.xx/24
            - xxxx:xxxx:0000:1010:0000:0000:0220:C001/64
            - 10.14.0.6/16
            gateway4: xxx.xxx.xxx.1
            gateway6: xxxx:xxxx:0000:1010:0000:0000:0000:0001
            match:
                macaddress: xx:xx:xxx:01:d0:e1
            nameservers: &id001
                addresses:
                - 67.207.67.3
                - 67.207.67.2
                search: []
            set-name: eth0
        eth1:
            addresses:
            - 10.129.22.148/16
            match:
                macaddress: xx:xx:xx:xx:xx:xx
            nameservers: *id001
            set-name: eth1

as they setup private network ip addresses for you on the fly.

So what needs to be added? Well DO does tell you how to add things manually. But does this kind of setup work for TransIP?

Private Network Block

To add a private network block do the following after ssh-ing into the box:

lshw -class network 

to find virtio0 serial or mac address.

*-virtio0
          description: Ethernet interface
          physical id: 0
          bus info: virtio@0
          logical name: ens3
          serial: xx:xx:xx:xx:44:29

You also need to know the available network by doing

ifconfig -a

ens7: flags=4098<BROADCAST,MULTICAST>  mtu 1500
        ether 52:54:00:56:e4:19  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens7 is shown here as this is the network that is not set yet and that can be used.

These two elements you can then add to your new block with proper network name and mac address:

ens7:
        addresses:
        - 10.0.0.0/8      
        match:
            macaddress: xx:xx:xx:19:44:29
        nameservers: *id001
        set-name: ens7

The initial block will need updating as well though

developing story..