What Is a Virtual IP? How to Get One

Every device you use has an IP address. But these IP addresses can take many form; if you deal with computers and networks, you've likely encountered a virtual IP address. But what is a virtual IP address? In this article, learn what a virtual IP is, how it's used, and why you might need one.

What is a virtual IP?

A virtual IP address, or VIP, is an IP address that is not tethered to any particular physical device or network interface. Instead, it often associates with a group of devices, servers, or domain names. 

This type of IP address can rotate among nodes. That means multiple machines connected to the Internet can share a VIP address. Each machine has a unique local address. But, externally, they all share a single virtual IP address if they’re based on one network interface card (NIC).

A regular IP address is assigned to a physical network adapter. This is not the case with a virtual Internet Protocol address, as it exists only on its software. Thus, it’s always active and can’t suffer from any physical failures.

Because the latter lacks a link to specific hardware, it allows more flexibility in routing network traffic.

VIPs are common in home and office networks to give each router a unique IP address. This type of IP can be configured as private IP addresses (used internally within a network). It’s also a good example of dynamic IP address. Dynamic IPs constantly change and a server assigns them on demand.

Once a server assigns a dynamic VIP, it becomes difficult to trace the physical location of its host servers. Be mindful that configuring a virtual IP to either of these categories depends on the use cases. 

Uses for VIPs include one-to-many network address translation (NAT), adaptation to non-critical failure, and mobility. 

What’s the primary purpose of a virtual IP?

The main objective of a virtual Internet Protocol address is to provide a single, consistent IP address that can represent multiple underlying resources such as network interfaces or servers. It typically eliminates the need for a host to rely on individual network interfaces. 

A VIP, therefore, frees computer networks from depending too heavily on any single piece of hardware. 

Initially, if a network interface failed, all connections tied to the interface were disrupted. But with virtual IP addressing in place, the network remains operational even if one interface fails. The ongoing connections keep functioning without interruption, as traffic is automatically rerouted through other functional interfaces. 

Systems running virtual IPs are reliable because any hiccups on adapters no longer affect active connections.

How does a virtual IP address work?

A virtual IP doesn't directly correspond to a specific physical network interface. It works by using a device like a load balancer to distribute incoming traffic to multiple servers. 

A load balancer is a device or software that sits between clients and servers in a network. It receives incoming requests from clients and intelligently distributes them across multiple servers that can handle the workload.

In this case, when a request arrives with the VIP address, the load balancer directs it to the most suitable server based on pre-defined rules. The virtual IP allows traffic to be routed to another functional server whenever one fails. 

The load balancer doesn't simply send requests to any available server. It uses various algorithms to consider factors like server load to choose the most optimal server for each request. Its job is to ensure the load is distributed evenly among the servers.

Steps to the virtual IP process

Essentially, these are the steps to a virtual IP functioning.

1. Assignment of the virtual IP and rotation. A virtual IP is assigned to multiple network interfaces, which are usually on different physical devices, such as servers or routers. The rotation is managed by network protocols and software that guarantee the VIP always points to an active node.
2. Client requests are sent to the VIP. When a user tries to access a network service, like a website, their request is sent to the VIP, who acts as a single point of contact for the user.
3. The load balancer distributes the traffic. The load balancer distributes the request to one of the available servers. This distribution ensures that no single server gets overloaded to maintain efficient operations.
4. The selected server processes the request. After processing, the server sends the response back to the load balancer.
5. Response forwarding: The load balancer forwards the server’s response to the user. This step allows the user to receive the requested information without knowing which server handled it.

The load balancer uses different algorithms to distribute traffic. These can include round-robin, where requests are sent to servers in a rotating order. Least connections, where requests are sent to the server with the fewest active connections, is another approach. In this case, none of the servers will become a bottleneck.

Example of how a virtual IP works

A good illustration is HSRP (Hot Standby Router Protocol). Suppose you have two routers, Router A and Router B, connected to a network. HSRP configures them to work in an "active/standby" mode.

Both routers have their own unique IP addresses for internal management. However, they share a single VIP address. This VIP acts as the main gateway for devices on the network to connect to the outside world.

One router, Router A, becomes the "active" router. It uses the VIP address and its real IP address. The active router is responsible for forwarding traffic between the network and the Internet.

Router B is in "standby" mode. It monitors the health of the active router. If the active router fails, the standby router takes over immediately.

In such a scenario, a virtual IP will step into the spotlight. When the active router fails, the standby router uses the VIP address to keep the network connection alive. 

The role of the HSRP virtual IP address is to provide seamless failover for routers in a network. This redundancy is crucial for critical systems that rely on constant internet access.

What’s the need for virtual IP?

Though most people are more familiar with traditional IPs, there are many reasons to use a virtual IP.

Load balancing

You can use a VIP with a load balancer to distribute incoming traffic across multiple servers. When you send a request to the VIP, it serves as a single point of contact that intelligently routes the request to the most suitable server.

By abstracting the individual server IPs behind the VIP, a user can efficiently manage load balancing without needing to know the specific server details. 

High availability

A virtual IP address offers a single service through multiple physical network interfaces (NICs). Take, for instance, a website with a VIP. If one NIC fails, the VIP address automatically redirects traffic to the remaining functional NICs. The website remains accessible with minimal disruption for users, even during hardware failures.

Network simplification

A single virtual IP address can function as the entry point for a group of servers. Network administrators only need to manage one VIP address.

We also don’t need as many separate IP addresses. These IPs save valuable resources, especially with the limited pool of IPv4 addresses.

Scalability 

Virtual IPs are invaluable for scaling network services efficiently. Maintaining well-organized networks is paramount, particularly in this era when billions of devices are constantly connected to the Internet. 

Engineers leverage virtual Internet Protocol addresses to effortlessly add or remove servers without the hassle of altering IP addresses or reconfiguring the network structure. 

This flexibility is crucial for upholding a streamlined, effective, and dependable online infrastructure.

Centralized management

A user can apply all updates and maintenance to all servers behind the VIP from a single location. It becomes much easier for administrators to handle the configuration. 

Security improvement

Security is another impressive feature of this technology. Virtual IP addresses can hide the actual IP addresses of the servers behind them, making it hard for attackers to infiltrate individual servers. 

Network address translation (NAT)

One of the main use cases for VIPs is in one-to-many NAT (Network Address Translation) scenarios. Here, a single VIP is advertised from a NAT device, such as a router, and incoming data packets destined for the VIP are routed to different actual IP addresses.

Cloud computing and virtual private clouds (VPCs)

VIPs let multiple virtual machines share a single IP address, enabling flexible allocation of network resources across different cloud instances. This remains effective even as underlying resources change or scale dynamically.

Benefits of using virtual IP addresses

Virtual IPs offer several advantages, particularly in environments where uptime and reliability are crucial. Here are some key benefits:

• High availability and failover. Virtual IPs are a cornerstone of high-availability systems. They assure that services remain accessible even if a network path fails. This is often managed by high availability protocols like the Virtual Router Reduncancy Protocol (VRRP).
• Simplified network management. Network administrators can manage traffic more efficiently. They easily redirect traffic, implement failover strategies, and adjust network configurations without disrupting services.
• Scalability. As organizations grow, their network infrastructure needs to scale accordingly. Virtual IPs make adding or removing servers from a pool easier without changing the IP addresses clients use.
• Enhanced security through abstraction. VIPs add an extra layer of security by obscuring the actual IP addresses of backend servers. Attackers find it hard to target specific servers directly.
• Mobility and flexibility. Because VIPs are not tied to specific hardware, they offer greater flexibility in routing network traffic. For example, if an application needs to move to a different server, the VIP can be reassigned without changing the application's IP address.

Challenges of managing virtual IPs

While virtual IPs offer significant advantages, managing them also comes with its own set of hurdles. Consider the following challenges of managing virtual IPs before continuing forward.

• IP configuration complexity. Apart from setting up an IP, maintaining it can be complex, especially in large networks. Admins have to be smart when managing virtual IP address configurations for servers.
• Complex monitoring and troubleshooting. Monitoring the health of servers behind a VIP requires specialized tools. Since traffic doesn't directly flow to a single server's IP, many need expertise to pinpoint issues with specific servers behind the VIP.
• Security concerns. While VIPs can mask real server IPs for some security benefit, it adds an extra layer of complexity to securing the network. A security protocol is necessary to protect the entire system behind the VIP.

What’s the difference between a virtual IP and floating IP?

The two are similar but not identical. A virtual IP acts like a label for a service within a closed network. 

Floating IPs are public Internet addresses assigned to a particular device. However, unlike a typical static IP, floating IPs can dynamically "float" around and attach to different servers within the network. 

It assures continued internet access for the service, even if the underlying device's physical location changes. 

The key difference is that a virtual IP is a private label for internal traffic, while a floating IP is a public address that grants external access regardless of internal changes.

How do servers use virtual IPs?

Multiple web servers can share the same IP address. The VIP allows them to distribute requests across multiple machines. 

Here's what you might consider for Windows and Mac:

• Windows Hyper-V. If you're using Windows 10 Pro or Enterprise, you can leverage Hyper-V to create virtual machines. Each VM can have its own internal IP address within the virtual network you configure.
• Mac with Parallels or VMWare. Similar to Hyper-V, virtualization software like Parallels or VMWare allows you to create VMs on your Mac. These VMs can have their own IP addresses within the virtual network.

Frequently asked questions

Where is virtual IP commonly used?

Data centers, cloud computing environments, and enterprise networks commonly use virtual IP services to distribute incoming traffic across multiple servers.

Can virtual IP be used for IPv6 networks?

Yes, it can. However, IPv6 introduces some differences in addressing and routing that may require adjustments to the configuration of virtual Internet Protocol address solutions.

Are there specific network protocols that are more compatible with virtual IP setups?

Yes, virtual Internet Protocol address setups are compatible with various network protocols like TCP/IP and UDP. They offer interoperability across different networking environments.