Client Cannot Communicate With the Server

When a client and a server cannot communicate with each other, the consequences depend on whether or not the client has a configuration cached from an earlier DHCP transaction. If it has, and if the lease is still valid, the client will use the cached data to configure the interface.

However, because the client has received no outside confirmation that this configuration is valid, there is no guarantee that the IP address, router address, and other information are valid. If the interface is connected to a network other than the one on which the configuration was received, one of two things can happen. Either errors may appear when other network services are started, or it may be impossible to communicate with other hosts on the network.

On the other hand, if no cache with an unexpired lease exists, the interface is not configured.