Linux Network Interface Naming Conventions

Interface Naming Convention

• Linux uses a predictable naming convention for network interfaces to identify which device and port corresponds to which interface.
• The naming convention starts with a two-character prefix indicating the interface type:
  • en: Ethernet
  • ib: InfiniBand
  • sl: Serial line IP (slip)
  • wl: Wireless local area network (WLAN)
  • ww: Wireless wide area network (WWAN)
• The naming convention follows a priority order:
  • Naming after the BIOS or firmware index (e.g., eno1)
  • Naming after the PCI express slot index (e.g., ens1)
  • Naming after the bus address (e.g., enp3s5)
  • Naming after the MAC address (e.g., enx78e7d1ea46da)
  • Naming using the legacy convention (e.g., eth0)

Configuration Files

• Configuration files for network interfaces are stored in /etc/systemd/network and /lib/systemd/network.
• Files with different suffixes have different purposes:
  • .netdev: creates virtual network devices (e.g., bridge or tun devices)
  • .link: sets low-level configurations for network interfaces
  • .network: sets up network addresses and routes
• The name of the file determines the order in which it is processed.
• The [Match] section in the file defines the network interface to which the configuration applies.

Network Interface Configuration

• The [Network] section in the file defines the settings for the device.
• The interface name should follow the word auto on the same line.
• Interfaces marked auto are brought up at boot time in the order they are listed.
• The iface line specifies the interface name, address family, and method used to configure the interface.
• Examples of address families and methods:
  • inet for TCP/IP networking
  • ipx for IPX networking
  • inet6 for IPv6 networking
  • loopback for loopback interfaces
  • dhcp for using IP settings from a DHCP server