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What is Virtual Firewall?

Virtualization is a common cloud computing technology. The abstraction of hardware resources for resource sharing is defined as virtualization. Virtualization can occur at various levels, including application, desktop, network, storage, and system virtualization. Virtual Machines (VM) are software replicas of real-world computers. Virtual machines are, in fact, collections of files that represent various components of physical computers. A single physical computer server can host numerous virtual machines (VMs) in a virtualized environment, and network traffic to and from the VMs is frequently limited to this server. With the advantages of virtualization comes the necessity for virtual security.

A firewall is a device that filters unwanted network traffic at network boundaries using software, hardware, or a combination of the two. An attacker can start, control, and stop the migration if the firewall policy is set incorrectly. The issue with the current trend of utilizing virtualization technology is that traditional network firewalls never observe VM-to-VM traffic. Virtual traffic is invisible to hardware firewalls since it never leaves the host. This problem can be solved with virtual firewalls.

Virtual firewall (VF) is a software-based firewall service that may filter packets based on IP address, ports, and protocols in virtual environments. VF policy for regulated communication of VMs can prevent VMs from illegal migration start, hijacking, or code injection during migration. Virtual firewalls are pre-installed as virtual security appliances on purpose-built virtual machines, making them simple to set up. Virtual firewalls can also be readily configured by integrating them with virtualization management tools/servers. Because the virtual firewalls and business applications are co-hosted on the same physical host, the virtual firewalls and business applications compete for the same hypervisor host resources (e.g., CPU, RAM).

What is Virtual Firewall?

Figure 1. What is Virtual Firewall?

How Does A Virtual Firewall Work?

For the flow of traffic, traditional packet filtering firewalls typically use either stateless or stateful approaches. The stateless traffic monitoring just examines each packet separately and is unable to detect a "flow" of traffic. The location of the flow within its lifetime is kept track of using state-of-the-art traffic monitoring.

The VF has at least two network interfaces, one internal (virtual) for communication with the host OS and the other external, which is connected to the outside network through a bridge. The network is only accessible to the host operating system (enough to support bridging between the guest VM running the Virtual Firewall and the network). In terms of the host OS, the VF is the default gateway (i.e., the only way for IP traffic to reach the outside world). Packet filtering, traffic monitoring, and management tools are all available on the Virtual Firewall platform. The default packet filtering policy on the VF permits traffic from the inner network to go to the outside network and, optionally, to a home network through an IPSec VPN. At the same time, it only accepts a small number of incoming connections.

What is the Purpose of a Virtual Firewall?

VF is a virtual machine that can act as a network firewall. A VF can be placed on the same physical computer as other virtual machines and configured to route all traffic to and from virtual machines through it.

To conduct dedicated firewall duties, VF appliances run on proprietary hardware. They are generally suitable for establishing modest security regulations, such as outbound Internet access and restricted protocol support, at the low end.

The main distinction with a virtualized host is that firewalls must run in a virtual network, therefore they are virtual software-based firewalls that run on dedicated VMs. Since the VF operating system is unaware that it is running under VMware, you are able to move your firewall which operates on a single board computer. Furthermore, you can easily shift VF from one cloud to another, making them highly cost-effective.

How To Create a Virtual Firewall?

You will need to create a new VM to execute the VF, assuming a VM is already installed and operational. Most of the VF have similar procedure, as examples we give two approaches for VMmare, and Proxmox.

VMware: the VM should have two ethernet interfaces, one of which is bridged to the external network and the other of which is for internal use exclusively.

The most typical approach for establishing a virtual firewall in VMware is given below:

  1. Expand Network from the navigation menu.
  2. Select the Firewalls section.
  3. Go to Firewall Rules
  4. Add Rule to create your first rule or additional rules.
  5. Go to Firewall Policies
  6. Add Policy to create your firewall policy.

Proxmox: A direction (IN or OUT) and an action make up FW rules (ACCEPT, DENY, REJECT). You can also give the macro a name. Macros are groups of rules and alternatives that have been pre-programmed. By prefixing rules with |, they can be deactivated.

Firewall rules syntax is given below:

|DIRECTION ACTION [OPTIONs] # disable rule
DIRECTION MACRO(ACTION) [OPTIONs] # use predefined macro

What are the Benefits of Virtual Firewall?

Because internet security is such an important factor to consider when establishing a network, the degree of a firewall should be carefully addressed. Firewalls make life more secure, not easier. The advantages acquired through virtual firewalls, as well as the growing demand for data protection and increasingly refined cyber-attacks, have led to the development of next-generation firewalls(NGFWs).

  • In Cloud systems, VF is seen as an essential integrated security aspect.
  • VFs are flexible and pliable, making them ideal for protecting virtualized environments.
  • VFs should be a fantastic alternative for protecting VMs between the start and finish migrations, given their capabilities.

Does Virtual Firewall Reduce Attack Surfaces?

Although security issues may continue to plague the Internet, existing tools and virtual firewall technologies might help us increase our defenses and reduce attack surfaces. When it comes to constructing firewall systems, there are a variety of approaches, designs, and technology options to consider.

To provide reasonable security of networks from undesirable attacks, a firewall system should be built. Rather than bringing the security provided by a perimeter firewall to your desktop, creating the virtual firewall should be considered as an upgrade in the context of better network connection management. Firewalls are currently exposed to a number of challenges, one of which is that their performance is deteriorating by the second as invasions become more harmful and difficult to halt.

Does the Virtual Firewall Provide Full-Scope Threat Prevention?

As previously said, creating virtual firewalls minimizes the attack surface. They cannot, however, give complete security against all hazards.

  • The VPN tunnel creates a breach in the firewall, allowing undesirable traffic to pass through from the inside or outside. Having a breach like this is extremely risky because viruses or worms could infiltrate the computer and then spread to other computers on the network. They are unable to defend against attacks that do not pass through or circumvent the firewall.
  • They are unable to maintain data integrity. Due to performance reduction, scanning all inbound communication for viruses is not practicable. There are far too many distinct techniques to encrypt binary files for network transmission, as well as far too many different architectures and viruses, to try to find them all.
  • Typically, they are unable to guarantee data confidentiality.

What is the Difference Between Physical Firewalls and Virtual Firewalls?

Physical firewalls can be implemented in both hardware and software. Their unique feature is that no other software runs on the server where the firewall is installed; in other words, the server's hardware is dedicated to only one program, the firewall application. Potential lack of integration between the physical firewall and the virtualization management system. This may obstruct provisioning automation and the updating of firewall rules, which may be constantly changing due to VM profile changes. Because virtual network traffic remains within the host, hardware firewalls are unable to filter it.

Virtual firewalls rely solely on software. Virtual firewalls were created in response to the drawbacks and limitations of physical firewalls. They differ from physical firewalls in that they share computing, networking, and storage resources with other virtual machines (VMs) on the virtualized host where they are deployed.

What is the Difference Between Virtual Firewalls and a Software Firewalls?

Software firewall components programmed from a single controller are quite useful, as they make it simple to create network rules. Imagine being able to set rules from a single location in the network rather than having to do so on each hop, node, or router. For network administrators, traffic paths and accompanying information are valuable. With this new networking standard, administrators can simply regulate, shape, and filter traffic because it all passes via a single point according to the rules applied.

Virtual firewalls are completely software-based security appliances that run on specially configured virtual machines. The initial generation of virtual firewalls worked in bridge mode, which means they could be put in a strategic location within the network, in this case, the virtual network of a virtualized host, exactly like their physical counterparts. Stateful or application firewalls are the two types of firewalls available. They eliminate the requirement for virtual network traffic to be routed back and forth from the virtualized host to the physical network. Deploying one is as simple as deploying any other virtual machine.

What is Best Virtual Firewall?

Zenarmor (Sensei) is a completely software-based quick firewall that can be installed almost anyplace. OPNsense is primarily known for being a good technology for packet filtering in a network, but it hasn't gotten much attention for how it can be used to flexibly filter traffic across a network using various switches. Zenarmor provides cutting-edge, next-generation features that aren't currently available in products like OPNsense.

Network Analytics, Application Control, and Web Content Filtering are some important features of Zenarmor.

What is Best Free Virtual Firewall?

The top free Virtual Firewalls are listed below.

  • OPNSense: OPNsense is a branch of the pfSense software and m0n0wall projects. The graphical user interface is available in a variety of languages, including French, Chinese, Japanese, Italian, Russian, and others. IPSec, VPN, 2FA, QoS, IDPS, Netflow, Proxy, Web filter, and other enterprise-level security and firewall functions are available in OPNSense. It can be downloaded as an ISO image or a USB installer and is compatible with 32bit and 64bit systems. OPNsense is primarily known for being a good technology for packet filtering in a network. Previous research has proven that OPNsense is a good technology for packet filtering in a network, but there hasn't been much focus on how it can be used to dynamically filter traffic across a network using several switches. The management of network traffic flows is at the heart of OPNsense. Flows are controlled by the flow table entries that are defined. A flow table entry consists of a packet header field match condition and an instruction, to put it simply.
  • pfSense® software: pfSense® software is an open-source stateful firewall based on the FreeBSD operating system and using a modified kernel. pfSense software is a commercial-level network firewall that is one of the most popular. pfSense software is offered as a physical device, a virtual appliance, and a binary download (community edition). pfSense is commonly used as a virtual firewall, with DHCP server, DNS server, WiFi access point, and VPN server all running on the same physical platform. Traffic shaping, VPNs utilizing IPsec or PPTP, captive portal, stateful firewall, network address translation, 802.1q support for VLANs, and dynamic DNS are all features of pfSense.

  • IPfire: IPfire is a security solution developed on top of Netfilter that is used by thousands of businesses worldwide. IPFire can function as a firewall, proxy server, or VPN gateway, depending on how it's set up. It has a lot of customizing options.

  • Untangle NG Firewall: Untangle NG is a single platform that contains everything you need to secure your organization's network. It has a stunning dashboard, which you can see in action here. It functions similarly to an app store in that you can enable or disable a specific program (module) depending on your needs. The NG Firewall platform, free apps, and a 14-day trial of paid features are all included in the FREE edition.

  • SmoothWall: SmoothWall is a free firewall with a simple online interface for configuring and managing it. Smoothwall express includes features such as LAN, DMZ, internal and external network firewalling, web proxy for speed, traffic statistics, and more. The web interface can be used to shut down or reboot the computer.

  • UFW (uncomplicated firewall): UFW is a firewall that works with Ubuntu. It has a command-line interface for controlling the Linux kernel packet filtering mechanism (Netfilter).

  • CSF (ConfigServer Security): CSF is a Linux server security solution that includes a stateful firewall, login detection, and security. RHEL/CentOS, CloudLinux, Fedora, OpenSUSE, Debian, Ubuntu, Slackware, OpenVZ, KVM, VirtualBox, XEN, VMware, Virtuozzo, and UML are all supported and tested with CSF.

  • Endian: Endian is Linux-based security software for home and small networks that is powerful, easy to install, and operate. It can turn a bare-metal hardware device into a strong and effective unified threat protection and management solution that includes a firewall, antivirus, VPN, and content filtering in one box. The stateful firewall protects your network from a variety of assaults and threats, as well as provides a well-protected VPN to secure the environment for your remote employees.