This change may affect how the service starts and stops on systemd Linux distros.

This is so any configurations which bind to a specific IP address can be supported properly. Before this change, the service may have failed to start because it came online before the network interface was configured with an IP address. Now, systemd will wait to start the service until after all network interfaces are configured or have failed to be configured. In cases where DHCP is used to configure a network interface, this may introduce a short delay in startup until network interface configuration either succeeds or fails.

Another result of this change is that mongod state is based on the networking state in systemd. Shutting down network services via systemd will now also stop mongod, and starting the network interface back up will start mongod again. This situation is extremely rare and does not usually happen except during OS shutdown and restart, or when a sysadmin would have intended all services to be unavailable (such as single-user mode).