If you ever need to, you can use a linux tool called ethtool to have the physical NICs on a server blink to identify it. This is especially useful in a remote-hands scenario when you aren’t physically behind the server.
To identify a NIC, use the -p or --identify option. Here’s how the manpage describes it.
$ man ethtool ... -p --identify Initiates adapter-specific action intended to enable an operator to easily identify the adapter by sight. Typically this involves blinking one or more LEDs on the specific network port.
To use it, add the network interface to the command.
$ ethtool -p eth0
If the command succeeds, it’ll keep the terminal busy and you can CTRL+C to exit it. If you’re testing this on a virtual NIC (VMware, Xen, …), you’ll be prompted that the feature is – logically – unavailable.
$ ethtool -p eth0 Cannot identify NIC: Operation not supported
Handy little tool!