To detect if a physical interface has been repaired, in.mpathd sends probes through the failed NIC. When an interface fails, all addresses are moved to another functional interface in the group. Because in.mpathd needs an address for probing so that it can detect repairs, you must configure a test IP address that will not move during the failover. Moreover, you should not allow a normal application to use this test address, because the failover of network access will not take place for these addresses. "How to Configure a Multipathing Interface Group with Two Interfaces" describes the steps that you perform. in.mpathd considers the interface repaired if it receives responses to 10 consecutive probe packets. Then, if in.mpathd detects a failure, failback of all network access takes place to the repaired interface.