Server does not recognize second VirtualBox Adapter

Solution 1:

have you got the interface configured in /etc/network/interfaces ? if not add the lines

 auto eth1
 iface eth1 inet dhcp

and restart

Solution 2:

To find your available interfaces use:

ip link

this will show you the interfaces you have, like so:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 08:00:27:1d:bd:93 brd ff:ff:ff:ff:ff:ff
3: enp0s8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000
    link/ether 08:00:27:c2:c1:92 brd ff:ff:ff:ff:ff:ff

Now add the last interface to the interfaces (in this case enp0s8)

vi /etc/network/interfaces

Type in [i] to edit (and move with arrow keys or before [i] hjkl (left, down, up, right))

auto enp0s8
iface enp0s8 inet dhcp

Save and close with [esc] :wq

Solution 3:

For latest versions (18.04) of the Ubuntu, network settings are stored in /etc/netplan/50-cloud-init.yaml.

1. Get device name with dmesg | grep enp (enp could be replaced to your device type).

2. Then insert (for device named enp0s8):

   enp0s8:
     addresses: []
     dhcp4: true
     optional: true
   

3. Then use sudo netplan apply to apply changes.

Solution 4:

Ubuntu Server 20.04 LTS uses Netplan for network configuration by default. The default configuration file in that case is /etc/netplan/00-installer-config.yaml.

• Get the device name with ip link

• Insert the device in the file /etc/netplan/00-installer-config.yaml (for example, enp0s8):

enp0s8:
  addresses: [192.168.2.89/24] # example
  gateway4: 192.168.2.1
  dhcp4: true

• Run sudo netplan apply to apply changes.

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