What is it called when two or more devices on a network have the same IP address?

When two or more devices on a network share the same IP address, it creates an IP address conflict. This situation arises because an IP address is meant to be unique within a network; each device must have its own unique address to properly communicate. When a conflict occurs, it can lead to connectivity issues, as the network becomes unable to determine which device should receive information intended for the shared IP address.

In a properly functioning network, each device requests a unique IP address, usually from a DHCP server, to avoid such conflicts. Resolving an IP address conflict may involve reconfiguring the network settings of the devices involved or ensuring that the DHCP server correctly assigns unique addresses.

The other options refer to different networking issues. Network collision relates to multiple devices attempting to send data over the same channel simultaneously, causing data loss or delay. Data packet loss occurs when packets of data traveling across the network fail to reach their destination due to various reasons, such as congestion or network failures. Subnet error involves issues related to the way networks are divided into subnets, often impacting routing and address management but not specifically concerning duplicated IP addresses.