Network Security Group vs Firewall. (NSG) is for controlling traffic flow for VMs and Firewall is for controlling traffic to and from the virtual machines.
Network Security Group (NSG) is for controlling traffic flow for VMs and Firewall is for controlling traffic to and from the virtual machines.
NSGs are useful when you want to control the inbound and outbound traffic at the VM level. It is also better when you want to standardize the security settings of all VMs within a subnet or across a set of subnets. NSGs can be configured using PowerShell, CLI, and vSphere Web Client. Hence, is helpful in the automation of the configuration settings.
A firewall, on the other hand, is useful when you want to control the inbound and outbound traffic on a per VM basis. Firewalls are applied at the port level on a virtual machine. You can also configure it using PowerShell, CLI or vSphere Web Client, although it’s not as straightforward as NSG. You can apply Firewall rules to individual network adapters as well as VMKernel adapters.
What is Network Security Group vs DVS?
Network Security Group is similar to Distributed Virtual Switch (DVS) in terms of functionality but works at a different layer of abstraction. DVS allows you to connect multiple vSphere clusters together, which is helpful for HA & DRS purposes. NSGs are for configuring rules for inbound and outbound traffic at the VM level. DVS can be configured using vSphere Web Client, while NSGs can be configured using vSphere Web Client, PowerShell or CLI. Both NSG & DVS can be managed by vCenter Server instances that are external to your ESXi hosts (example: VCSA). This makes administration more centralized, which helps reduce administrative overhead.
What is Network Security Group vs Portgroups?
Network Security Groups are similar to Portgroups in terms of functionality but work at a different layer of abstraction. Portgroups are for configuring rules for inbound and outbound traffic at the VM level on a single ESXi host. You can use Portgroups when you need to manage common rules across all VMs on a single ESXi host (for example during maintenance tasks).
On the other hand, NSGs can be configured using vSphere Web Client, PowerShell or CLI, which is helpful in the automation of the configuration settings. Portgroups can be configured using vSphere Web Client only. You can also configure Portgroups using ESXCLI (example for portgroup rename) but that requires SSH to be enabled on your vCenter Server instance which is not recommended.
What are the benefits of using a Firewall?
Firewalls provide the following benefits:
Security: Firewalls can be used to enforce security policies for your VMs. For example, you can use a firewall to prevent a VM from making unauthorized external connections.
Performance: Firewalls can be used to optimize network performance by allowing or disallowing specific traffic. For example, you can use a firewall rule to allow only the required network traffic and block unnecessary traffic.
Visibility & Control: Firewalls provide visibility into the inbound and outbound traffic flow and therefore they provide you with control over the VMs’ traffic.
Monitoring: Firewalls can be used to monitor the inbound and outbound traffic flow for troubleshooting purposes. For example, if a VM is not able to connect to an external resource, you can use monitoring rules on the firewall to troubleshoot the issue.