The use of identical network configurations at both primary and DR sites means that after the failover event has been managed, services can be rerouted back to the primary site with minimal reconfiguration, which eases the failback process. Dynamic routing protocols help in automating route adjustments during the failover and failback process. Static IPs might cause network conflicts or require manual intervention during rerouting, hence they are not the best choice. Different subnet schemes could make failback process complex due to the need for network reconfiguration. Lastly, the presence of a single NIC would represent a single point of failure and does not relate directly to the process of switching back and forth between primary and disaster recovery sites.