docker/cli · error

%s is not a valid mac address

Error message

%s is not a valid mac address

What it means

Error "%s is not a valid mac address" thrown in docker/cli.

Source

Thrown at cli/command/container/opts.go:352

	NetworkingConfig *network.NetworkingConfig
}

// parse parses the args for the specified command and generates a Config,
// a HostConfig and returns them with the specified command.
// If the specified args are not valid, it will return an error.
//
//nolint:gocyclo
func parse(flags *pflag.FlagSet, copts *containerOptions, serverOS string) (*containerConfig, error) {
	var (
		attachStdin  = copts.attach.Get("stdin")
		attachStdout = copts.attach.Get("stdout")
		attachStderr = copts.attach.Get("stderr")
	)

	// Validate the input mac address
	if copts.macAddress != "" {
		if _, err := net.ParseMAC(strings.TrimSpace(copts.macAddress)); err != nil {
			return nil, fmt.Errorf("%s is not a valid mac address", copts.macAddress)
		}
	}
	if copts.stdin {
		attachStdin = true
	}
	// If -a is not set, attach to stdout and stderr
	if copts.attach.Len() == 0 {
		attachStdout = true
		attachStderr = true
	}

	var err error

	swappiness := copts.swappiness
	if swappiness != -1 && (swappiness < 0 || swappiness > 100) {
		return nil, fmt.Errorf("invalid value: %d. Valid memory swappiness range is 0-100", swappiness)
	}

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at cli/command/container/opts.go:352 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/06c11abc5028b46f.json. Report an issue: GitHub.