eth1

Eth1 is a conventional label used in Linux and other Unix-like operating systems to refer to the second Ethernet network interface. The name derives from early kernel device naming, where the first Ethernet device was eth0 and subsequent devices followed in numeric order. On modern systems, interface names are often generated by predictable rules based on hardware location, such as enp3s0 or enp2s1, which can differ from eth1 depending on the hardware and distribution. Nevertheless, eth1 remains common in older installations, virtual machines, and certain network scripts.

In a running system, eth1 corresponds to a concrete network interface, which can be listed and inspected with commands such as ip addr show dev eth1 or ifconfig eth1 (when the latter is installed). The interface exposes properties including its MAC address, a configured IP address (static or via DHCP), an MTU, and a link state (UP or DOWN).

Configuration of eth1 depends on the operating system and network management tooling. In Debian-based systems, legacy networks might be configured in /etc/network/interfaces, while newer deployments use netplan. Red Hat-based systems may use NetworkManager or network-scripts. In many setups, eth1 serves as a secondary network path, such as a management interface, a storage network, or a guest network in virtualization environments, and may be linked to a bridge or bonded with other interfaces for redundancy or throughput.

Notes: The interface name eth1 is not guaranteed to exist on every system; it may be renamed or omitted depending on hardware, virtualization, and naming rules. Predictable naming can yield different labels, and udev or system configuration can override them. In virtualization, eth1 may be the second VM NIC or a host interface used for external networking.