The sending of an early notification when a guest migrates in a virtual machine system is described. A guest hosted by a computer system is migrating from a source hypervisor to a target hypervisor. During the migration, the source hypervisor stops transmission of outbound packets from the guest. A signal is sent to the target hypervisor after stopping the transmission and before completing migration of the guest. The signal requests that a notification containing network addresses of the guest be sent to network devices associated with the target hypervisor.