Unused Virtual IPs: Why Optimizing Your Load Balancer Configuration Matters

The modern Application Delivery Controller (ADC) is responsible for both the availability and security of applications, making it a critical component of the network. In today’s dynamic business environment, ADC configurations are constantly changed and modified. In fact, network engineers in large organizations are charged with processing many ADC change requests each week.

The complexity of ADC infrastructure adds a significant burden to network engineers. Luckily, there are effective ways to manage these challenges. One such challenge is optimizing load balancer configurations. In the following example, let’s consider an organization functioning on a large F5 ADC infrastructure. Here’s a basic explanation of various F5 terminologies. The F5 BIG-IP platform offers many solutions, and the most cutting-edge modules are BIG-IP Local Traffic Manager (BIG-IP LTM) and BIG-IP Domain Name Server (BIG-IP DNS), earlier referred as F5 BIG-IP Global Traffic Manager (BIG-IP GTM).

The first step in load balancing is assigning names to IPs. The BIG-IP DNS device tells you the best IP (an actual server or a virtual IP) to route for the requested application. Multiple DNS devices are deployed to ensure high availability of applications. The main configuration element in a BIG-IP DNS is Wide IP or WIP and is usually attached to many pools that contain the IP’s of the end servers.

The BIG-IP LTM module ensures high availability of applications and does the actual load-sharing, HTTP-caching, SSL-offloading, web acceleration, etc.. The main configuration element on BIG-IP LTM is referred as the “Virtual IP,” the “VIP” or simply the “Virtual Server”. It is the key component and starting point to building ADC configurations to deploy an application. The VIP is the destination (combination of IP and port) to which traffic requests will be sent, where profiles and other configuration options are defined and much more.

What is an unused virtual server?

One particular virtual server or a whole set may not see any traffic for three months or more. However, many network teams continue to maintain these virtual servers without realizing they are going unused, wasting significant time and resources. This leaves many unnecessary IP ports open and their IPs unused, too.

It’s not uncommon for 10 to 20 percent of an enterprise’s configurations to be inactive without the network team realizing it. Whenever network teams migrate something to a new environment or to the cloud, virtual servers can unintentionally be left behind. And, as soon as you direct DNS records to new code (cloud or a different environment), the old code is left untouched and unused. This also occurs when multiple teams are involved in the migration process or when the number of unused VIPs is too difficult to track manually.

Given applications are now at the core of so many businesses, decommissioning virtual servers without proper impact analysis is simply too risky.

Benefits of VIP decommissioning

Network teams must stop managing unused configurations, especially when they have plans to replace existing hardware or perform a version upgrade. By unintentionally maintaining these inactive objects, they are incurring unnecessary overhead costs for their enterprises. The benefits of decommissioning unused virtual servers are:

  • More efficient allocation of IP resources. Unused IPs can be used elsewhere
  • Reduced service costs
  • The elimination of unnecessary management and monitoring overhead resulting from unused virtual servers

Automate the Decommissioning of Virtual Servers

With AppViewX’s Application Delivery Automation solution, decommissioning virtual servers can be done in a standardized and automated way. Users can generate actionable reports to view lists of unused virtual servers. Then, using the AppViewX Platform automated change management processes, users can define a workflow and automate the decommissioning of the virtual IPs they identified either individually or in bulk. The unused or free IPs are then moved to IPAM systems.

The management of unused virtual IPs is just one of the many challenges that NetOps teams face. Read the white paper Five Common Business Challenges in ADC Management: Tackling NetOps’ Issues Using Automation to learn more about these common roadblocks and how to overcome them.


  • Load Balancer
  • NetOps Automation
  • Network Automation
  • Network Infrastructure Management

About the Author

Nishevitha Ramamoorthy

Product Marketing Manager - AppViewX CERT+

Nishevitha is the product marketer at AppViewX. She writes, does research, and builds strategies to communicate the product's value to prospective buyers.

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