eth0eth1

Eth0eth1 is not a standard or officially recognized network interface name. It appears to be a concatenation of two common interfaces, eth0 and eth1, rather than a single, valid device name used by operating systems or networking stacks.

In practice, the string may show up as a misconfiguration, a parsing error, or a log artifact. Possible sources include scripts or configuration files that join interface names without a proper separator, corrupted data exports, or documentation examples where multiple interfaces are listed together without clear delimitation. Some embedded systems or custom firmware might generate nonstandard identifiers under limited naming schemes.

On a typical Linux system, interface names follow the kernel’s naming scheme or the predictable network interface names introduced by udev, such as eth0, enp3s0, enp0s31f6, or bond and bridge devices like bond0 or br0. If a device appears as “eth0eth1” in configuration, it is usually a sign of misnaming rather than a real hardware interface. Verifying with commands such as ip link show, ls /sys/class/net, or nmcli device status can confirm the actual devices recognized by the system. Investigations should include checking network configuration files (for example, /etc/network/interfaces, /etc/netplan/*.yaml, or NetworkManager profiles) and udev rules (/etc/udev/rules.d/).

Resolution typically involves correcting the naming in scripts or configuration, or re-creating the proper interface entries (for example, eth0 and eth1, or a bonded/bridged device if that is the intended setup). Adopting predictable network naming conventions helps prevent similar ambiguities.