Linux and DevOps

When assigning static IPs, devices use GARP to check if an IP address is already in use on the network. This is a simple and effective way to prevent IP conflicts.

For example, before assigning itself an IP, a device sends a GARP request. If no response is received, it proceeds with the configuration.

In high-availability setups like Hot Standby Router Protocol (HSRP) or Virtual Router Redundancy Protocol (VRRP), GARP is used to broadcast the ownership of a virtual IP address.

This ensures that devices communicate with the active router, even during failover events.

Example, If a backup router takes over the virtual IP after the primary router fails, it sends a GARP message to update all devices' ARP tables with the new MAC address.

GARP is often used to announce the presence of a new node or device on the network. This ensures other hosts can immediately recognize and communicate with the new device.

Here is an example:
When a new virtual machine or router interface comes online, it sends GARP to let the network know it’s available.

GARP helps devices update their ARP caches when a MAC address changes or when a new device joins the network. This avoids communication disruptions due to outdated IP-to-MAC mappings.

For example, A server changing its network interface card (NIC) can use GARP to inform other devices of its new MAC address.