About Virtual Wire Pair

The term "Virtual Wire" is commonly associated with network security appliances, such as firewalls or intrusion prevention systems, operating in a transparent or bridge mode.

A "Virtual Wire Pair" typically consists of two interfaces, one connected to the inbound traffic path and the other to the outbound traffic path. Together, they form a transparent bridge that allows network traffic to flow through the security device without requiring IP address changes on the devices connected to the network.

Here's a basic overview of how a Virtual Wire Pair works:

• Ingress Interface:

  • Connects to the incoming or upstream network segment.

• Egress Interface:

  • Connects to the outgoing or downstream network segment.

• Transparent Operation:

  • The security device, operating in a transparent or bridge mode, allows traffic to flow seamlessly between the two interfaces without actively participating in IP routing.

• Security Inspection:

  • The security device can inspect and analyze the traffic passing through the Virtual Wire Pair, applying security policies without altering the original IP addresses of the devices in the network.

This setup is useful when introducing security devices into an existing network architecture without requiring significant changes to IP addressing or network configurations. It provides a non-disruptive way to enhance security by monitoring and controlling traffic flows.

In Fortinet's FortiGate firewall devices, a "Virtual Wire Pair" refers to a configuration mode that allows the firewall to operate in a transparent or bridge mode, without requiring changes to the existing IP addresses on the network. This mode is useful for seamlessly integrating the firewall into an existing network architecture without causing disruptions.

Here's how a Virtual Wire Pair works in FortiGate:

• Ingress and Egress Interfaces:

  • The Virtual Wire Pair consists of two interfaces, typically named "internal" and "external." The "internal" interface connects to the internal network (ingress), while the "external" interface connects to the external network (egress).

• Transparent Bridge Mode:

  • The FortiGate firewall operates as a transparent bridge, allowing traffic to flow through the Virtual Wire Pair without actively participating in IP routing.

• Security Inspection:

  • While not altering the IP addresses, the firewall inspects and analyzes the traffic passing through the Virtual Wire Pair, applying security policies based on predefined rules.

• Non-Disruptive Integration:

  • Because the FortiGate is operating transparently, devices on the network do not need to be reconfigured with new IP addresses. This allows for a non-disruptive integration of the firewall into an existing network.

• Advanced Features:

  • FortiGate devices in Virtual Wire Pair mode can still provide advanced security features, such as intrusion prevention, antivirus scanning, and application control, without requiring changes to IP addresses.

When configuring a Virtual Wire Pair on a FortiGate device, administrators typically define the ingress and egress interfaces and configure security policies to control traffic flow through the firewall. This mode is particularly useful in scenarios where a seamless security integration is required within an existing network infrastructure.

In networking, both "transparent mode" and "bridge mode" refer to similar concepts where a network device operates as a bridge or a pass-through, allowing traffic to flow through without actively participating in routing or changing the IP addresses of the devices on the network. These terms are often used interchangeably, but there can be some nuances depending on the specific device or context.

Here's a brief explanation of each:

• Transparent Mode:

  • In this mode, a network device operates transparently, without requiring changes to the IP addresses or network topology. It allows the device to seamlessly integrate into an existing network.

  • Transparent mode is often associated with security devices like firewalls or intrusion prevention systems, where the device monitors and filters traffic without being directly involved in the routing process.

• Bridge Mode:

  • Bridge mode is a generic term used to describe a network device operating as a bridge. A bridge connects two separate network segments and allows traffic to pass through without modifying the IP addresses.

  • In the context of wireless routers or access points, bridge mode can refer to a configuration where the device connects two separate wired networks wirelessly, acting as a bridge between them.

For Fortinet's FortiGate firewall devices, the term "transparent mode" is commonly used to describe a mode where the firewall operates as a transparent bridge. In this context, the terms "transparent mode" and "bridge mode" are often used interchangeably to convey the idea that the firewall is not actively routing traffic but is instead transparently passing it through while performing security functions.

In summary, both terms generally mean that the device operates as a bridge, allowing traffic to flow through without changing IP addresses, and the specific terminology might depend on the device or vendor.