If you have attended some of my classes and read some of my books, you know that I really like [Proxmox](https://www.proxmox.com/en/). I have several Proxmox clusters that I use for my training courses and to develop labs to learn new cybersecurity skills (offensive and defensive techniques).
You can instantiate Linux systems such as [Kali Linux](https://www.kali.org/), [WebSploit](https://websploit.org), [Parrot](https://parrotlinux.org/), [BlackArch](https://blackarch.org/), [Security Onion](https://securityonion.net), [RedHuntOS](https://github.com/redhuntlabs/RedHunt-OS), and others in different VMs to practice and learn new skills in a safe environment.
Systems like [Security Onion](https://securityonion.net) and [RedHuntOS](https://github.com/redhuntlabs/RedHunt-OS) come with with [Snort](https://www.snort.org/), [Suricata](https://suricata-ids.org/), [ELK](https://www.elastic.co/what-is/elk-stack), and many other security tools that allow you to monitor your network.
You have to setup [port mirroring](https://en.wikipedia.org/wiki/Port_mirroring) for IDS/IPS systems like Snort to be able to monitor traffic. In Proxmox, you can setup [Linux bridges](https://pve.proxmox.com/wiki/Network_Configuration) and [Open vSwitch (OVS) bridges](https://pve.proxmox.com/wiki/Open_vSwitch).
## OVS Setup
I strongly recommend to use OVS bridges to send traffic to your Security Onion VM (or whatever other VM you would like to capture packets or monitor for IDS/IPS functions.
- **Note:** A bridge is another term for a Switch. It directs traffic to the appropriate interface based on mac address. Open vSwitch bridges should contain raw ethernet devices, along with virtual interfaces such as OVSBonds or OVSIntPorts. These bridges can carry multiple vlans, and be broken out into 'internal ports' to be used as vlan interfaces on the host.
1. First, you need to update the package index and then install the Open vSwitch packages by executing:
```
apt update
apt install openvswitch-switch
```
2. Then you can create an OVS bridge and assign the interfaces of each VM that you want to capture packets to that OVS bridge.
3. You then configure the `tap` interfaces. These are only visible in the system shell (not in the Proxmox GUI) and are added automatically for VMs attached to an OVS-bridge interface. The naming convention of the tap interfaces is based on the ID of the VM they are assigned to, with the name `tap[VM-ID]i[interface#]`.
For example, these are some of the interfaces in one of the Proxmox nodes/servers in one of my clusters:
```
┌─[root@hermes]─[~]
└──╼ #ip -brie a
lo UNKNOWN 127.0.0.1/8 ::1/128
enp0s31f6 DOWN
enp1s0f0 UP
enp1s0f1 DOWN
enp3s0f0 UP
enp3s0f1 DOWN
vmbr0 UP 192.168.78.10/24 fe80::92e2:baff:fe84:dbd0/64
vmbr1 UP 10.1.1.10/24 fe80::a236:9fff:fe1c:2430/64
vmbr2 UNKNOWN fe80::f84b:12ff:fe3c:6e61/64
ovs-system DOWN
vmbr3 UNKNOWN fe80::208a:52ff:fe6d:504f/64
tap109i0 UNKNOWN
fwbr109i0 UP
fwpr109p0@fwln109i0 UP
fwln109i0@fwpr109p0 UP
tap109i1 UNKNOWN
tap109i2 UNKNOWN
fwbr109i2 UP
fwpr109p2@fwln109i2 UP
fwln109i2@fwpr109p2 UP
tap112i0 UNKNOWN
fwbr112i0 UP
fwpr112p0@fwln112i0 UP
fwln112i0@fwpr112p0 UP
tap112i1 UNKNOWN
fwbr112i1 UP
fwpr112p1@fwln112i1 UP
fwln112i1@fwpr112p1 UP
tap114i0 UNKNOWN
tap119i0 UNKNOWN
fwbr119i0 UP
fwpr119p0@fwln119i0 UP
fwln119i0@fwpr119p0 UP
tap119i1 UNKNOWN
fwbr119i1 UP
fwpr119p1@fwln119i1 UP
fwln119i1@fwpr119p1 UP
tap121i0 UNKNOWN
veth122i0@if59 UP
fwbr122i0 UP
fwpr122p0@fwln122i0 UP
fwln122i0@fwpr122p0 UP
veth122i1@if64 UP
fwbr122i1 UP
fwpr122p1@fwln122i1 UP
fwln122i1@fwpr122p1 UP
tap126i0 UNKNOWN
fwbr126i0 UP
fwpr126p0@fwln126i0 UP
fwln126i0@fwpr126p0 UP
veth130i0@if73 UP
fwbr130i0 UP
fwpr130p0@fwln130i0 UP
fwln130i0@fwpr130p0 UP
veth136i0@if78 UP
fwbr136i0 UP
fwpr136p0@fwln136i0 UP
fwln136i0@fwpr136p0 UP
fwbr109i1 UP
fwln109o1 UNKNOWN
veth115i0@if89 UP
fwbr115i0 UP
fwln115o0 UNKNOWN
tap106i0 UNKNOWN
fwbr106i0 UP
fwpr106p0@fwln106i0 UP
fwln106i0@fwpr106p0 UP
tap106i1 UNKNOWN
```
`tap106i0` is the first (0) virtual interface created for VM with ID 106, and `tap106i1` is the second such interface.
In order to send all traffic on the OVS bridge to the Security Onion VM (VM 106). I use the following command in the Proxmox node:
`vmbr3` is the OVS bridge for that internal network. This creates a new “mirror” object named “span1”. Span1 will send any IP traffic on the `vmbr3` OVS bridge to the second virtual interface on VM 106 (tap106i1).
