What Is a Virtual IP? How to Get One
Learn what virtual IP (VIP) addresses are, how they are used in load balancing and high availability, and how to configure them.
Virtual IP Address Overview
A virtual IP (VIP) address is an IP that is not tied to a single physical network interface. Instead, it can move between devices or be shared by multiple servers. Clients connect to the VIP, while the underlying infrastructure directs traffic to the appropriate real server or node.
VIPs are commonly used in load balancers, failover clusters, and high-availability configurations where service continuity is critical.
Common Use Cases for Virtual IPs
In load-balancing setups, a VIP fronts a pool of backend servers. The load balancer routes incoming connections to different servers based on health checks and balancing algorithms. If one server fails, the VIP remains reachable while traffic is sent to healthy nodes.
High-availability clusters use VIPs to allow a standby server to take over if the primary fails. The VIP shifts to the standby node, and clients continue using the same IP and hostname without reconfiguration.
Configuration Considerations for Virtual IPs
Configuring VIPs involves coordinating address assignment, health checks, and failover behavior. Solutions range from simple keepalive scripts on small clusters to complex appliance-based load balancers in large environments.
When planning VIPs, consider DNS caching, session persistence, and SSL/TLS termination. Proper design ensures that moving or balancing traffic behind a VIP is transparent to end users.