Creating a free5GC VM and Setting up Network

In this demo we will exercise:

Cloning an existing VM, and install free5GC on it
Setting up the networking for the free5GC VM

Tips

Refer to video Clone VM and Change IP.

1. Check up an existing VM for Cloning

Launch VirtualBox, and make sure the Ubuntu VM (ubuntu) we created before can boot up, then:

Log in into the VM using SSH from the host machine, and check if the VM has internet access
Make sure you have done sudo apt update and sudo apt upgrade (or you can do it again)
Shutdown the VM. You can:
use command sudo shutdown -P now, or
click the “Close Window” of the Ubuntu VM terminal and choose the middle option (better not force to turn off the machine power)
later if you just want to reboot, enter sudo shutdown -r now

2. Create a free5GC VM

First let’s clone a new VM:

Select an existing VM (ubuntu) and click the buttons on the right: / Snapshopts / Clone.
Name the new VM free5gc.
The MAC address rule: Create new MAC addresses for all network cards.
Choose the Link cloning option (or you can also choose to complete clone the VM if you like).

After the new VM is created:

Start up the new free5gc VM, and use the same username and password to log in.
In the Ubuntu terminal, issue ping and ifconfig again to make sure it has internet access, and also make note of the IP address of the Host-only network interface.
- for example the IP could still be 192.168.56.101, and the interface name is enp0s8.
Log in into free5gc VM using SSH, and make sure all things working properly.

3. Change hostname

The cloned free5gc VM still has host name ubuntu (or the name you gave it in the original VM). Let’s rename the VM to free5gc. You can do this by editing the file /etc/hostname (using vi or nano):
```bash
sudo nano /etc/hostname

or

sudo vi /etc/hostname
`` In the file, change ubuntu intofree5gc. If you are using nano ，you can pressCtrl-Oto save the file, thenCtrl-X` to exit.

Let’s also change the file /etc/hosts by replacing the ubuntu inside into free5gc:
bash sudo nano /etc/hosts

New content of the file /etc/hosts looks like this:
bash 127.0.0.1 localhost 127.0.1.1 free5gc ...

The changes will take effect after next reboot.

4. Setting Static IP Address

The Host-only network interface, by default, gets its IP address through DHCP. The cloned free5gc VM seems to have trouble obtaining new IP address. We can change the host-only interface to use static IP address instead, which can save a lot of trouble later.

Here let’s fix the static IP address as 192.168.56.101:
bash cd /etc/netplan ls 00-installer-config.yaml cat 00-installer-config.yaml
The original content of the file 00-installer-config.yaml looks like:
```yaml

This is the network config written by 'subiquity'

network:
ethernets:
enp0s3:
dhcp4: true
enp0s8:
dhcp4: no
addresses: [192.168.56.101/24]
version: 2
First check if the new content is correct:bash
sudo netplan try
Press enter to exit, if successful. The apply tne new interface setting:bash
sudo netplan apply
Run `ifconfig` to see if the network setting has been changed correctly:bash
enp0s3: flags=4163 mtu 1500
inet 10.0.2.15 netmask 255.255.255.0 broadcast 10.0.2.255
inet6 fe80::a00:27ff:fec4:254f prefixlen 64 scopeid 0x20
ether 08:00:27:c4:25:4f txqueuelen 1000 (Ethernet)
RX packets 2 bytes 1180 (1.1 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 18 bytes 1894 (1.8 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

enp0s8: flags=4163 mtu 1500
inet 192.168.56.101 netmask 255.255.255.0 broadcast 192.168.56.255
inet6 fe80::a00:27ff:fe7e:ada6 prefixlen 64 scopeid 0x20
ether 08:00:27:7e:ad:a6 txqueuelen 1000 (Ethernet)
RX packets 8420 bytes 531867 (531.8 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 10887 bytes 823487 (823.4 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 6621 bytes 596035 (596.0 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 6621 bytes 596035 (596.0 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
We can also check the routing table, just to have a grasp of what is going on regarding the network setting:bash
route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.2.2 0.0.0.0 UG 100 0 0 enp0s3
10.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 enp0s3
10.0.2.2 0.0.0.0 255.255.255.255 UH 100 0 0 enp0s3
192.168.56.0 0.0.0.0 255.255.255.0 U 0 0 0 enp0s8
```

For the display above, we learn that the Host-only network 192.168.56.0/24 does not have internet access by itself (even though we can access it using SSH from the host machine). Internet access is through the NAT network 10.0.2.0/24, with the gateway being 10.0.2.2 (provided by VirtualBox).
Now we can SSH into free5gc VM using 192.168.56.101:
bash ssh 192.168.56.101 -l ubuntu
This is also how we interact with free5gc VM from now on.