diff --git a/cmd/sslcert/main.go b/cmd/sslcert/main.go
index facd646..efb4971 100644
--- a/cmd/sslcert/main.go
+++ b/cmd/sslcert/main.go
@@ -224,20 +224,20 @@ func (program *checkProgram) Done() {
 // if the arguments made sense.
 func (program *checkProgram) CheckArguments() bool {
 	if program.hostname == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no hostname specified")
+		program.plugin.SetState(plugin.StatusUnknown, "no hostname specified")
 		return false
 	}
 	if program.port < 1 || program.port > 65535 {
-		program.plugin.SetState(plugin.UNKNOWN, "invalid or missing port number")
+		program.plugin.SetState(plugin.StatusUnknown, "invalid or missing port number")
 		return false
 	}
 	if program.warn != -1 && program.crit != -1 && program.warn <= program.crit {
-		program.plugin.SetState(plugin.UNKNOWN, "nonsensical thresholds")
+		program.plugin.SetState(plugin.StatusUnknown, "nonsensical thresholds")
 		return false
 	}
 	if _, ok := certGetters[program.startTLS]; !ok {
 		errstr := "unsupported StartTLS protocol " + program.startTLS
-		program.plugin.SetState(plugin.UNKNOWN, errstr)
+		program.plugin.SetState(plugin.StatusUnknown, errstr)
 		return false
 	}
 	program.hostname = strings.ToLower(program.hostname)
@@ -262,13 +262,13 @@ func (program *checkProgram) getCertificate() error {
 // matches the requested host name.
 func (program *checkProgram) checkSANlessCertificate() bool {
 	if !program.ignoreCnOnly || len(program.extraNames) != 0 {
-		program.plugin.SetState(plugin.WARNING,
+		program.plugin.SetState(plugin.StatusWarning,
 			"certificate doesn't have SAN domain names")
 		return false
 	}
 	dn := strings.ToLower(program.certificate.Subject.String())
 	if !strings.HasPrefix(dn, fmt.Sprintf("cn=%s,", program.hostname)) {
-		program.plugin.SetState(plugin.CRITICAL, "incorrect certificate CN")
+		program.plugin.SetState(plugin.StatusCritical, "incorrect certificate CN")
 		return false
 	}
 	return true
@@ -298,7 +298,7 @@ func (program *checkProgram) checkNames() bool {
 		certificateIsOk = program.checkHostName(name) && certificateIsOk
 	}
 	if !certificateIsOk {
-		program.plugin.SetState(plugin.CRITICAL, "names missing from SAN domain names")
+		program.plugin.SetState(plugin.StatusCritical, "names missing from SAN domain names")
 	}
 	return certificateIsOk
 }
@@ -308,7 +308,7 @@ func (program *checkProgram) checkNames() bool {
 // values.
 func (program *checkProgram) checkCertificateExpiry(tlDays int) (plugin.Status, string) {
 	if tlDays <= 0 {
-		return plugin.CRITICAL, "certificate expired"
+		return plugin.StatusCritical, "certificate expired"
 	}
 
 	var limitStr string
@@ -317,15 +317,15 @@ func (program *checkProgram) checkCertificateExpiry(tlDays int) (plugin.Status,
 	switch {
 	case program.crit > 0 && tlDays <= program.crit:
 		limitStr = fmt.Sprintf(" (<= %d)", program.crit)
-		state = plugin.CRITICAL
+		state = plugin.StatusCritical
 
 	case program.warn > 0 && tlDays <= program.warn:
 		limitStr = fmt.Sprintf(" (<= %d)", program.warn)
-		state = plugin.WARNING
+		state = plugin.StatusWarning
 
 	default:
 		limitStr = ""
-		state = plugin.OK
+		state = plugin.StatusOK
 	}
 
 	statusString := fmt.Sprintf("certificate will expire in %d days%s",
@@ -351,7 +351,7 @@ func (program *checkProgram) setPerfData(tlDays int) {
 func (program *checkProgram) RunCheck() {
 	err := program.getCertificate()
 	if err != nil {
-		program.plugin.SetState(plugin.UNKNOWN, err.Error())
+		program.plugin.SetState(plugin.StatusUnknown, err.Error())
 	} else if program.checkNames() {
 		timeLeft := time.Until(program.certificate.NotAfter)
 		tlDays := int((timeLeft + 86399*time.Second) / (24 * time.Hour))
diff --git a/cmd/zoneserial/main.go b/cmd/zoneserial/main.go
index f00547a..e8bc7d6 100644
--- a/cmd/zoneserial/main.go
+++ b/cmd/zoneserial/main.go
@@ -88,7 +88,7 @@ func NewProgram() program.Program {
 // Terminate the monitoring check program.
 func (program *checkProgram) Done() {
 	if r := recover(); r != nil {
-		program.plugin.SetState(plugin.UNKNOWN, "Internal error")
+		program.plugin.SetState(plugin.StatusUnknown, "Internal error")
 		program.plugin.AddLinef("Error info: %v", r)
 	}
 	program.plugin.Done()
@@ -97,23 +97,23 @@ func (program *checkProgram) Done() {
 // Check the values that were specified from the command line. Returns true if the arguments made sense.
 func (program *checkProgram) CheckArguments() bool {
 	if program.hostname == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no DNS hostname specified")
+		program.plugin.SetState(plugin.StatusUnknown, "no DNS hostname specified")
 		return false
 	}
 	if program.port < 1 || program.port > 65535 {
-		program.plugin.SetState(plugin.UNKNOWN, "invalid DNS port number")
+		program.plugin.SetState(plugin.StatusUnknown, "invalid DNS port number")
 		return false
 	}
 	if program.zone == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no DNS zone specified")
+		program.plugin.SetState(plugin.StatusUnknown, "no DNS zone specified")
 		return false
 	}
 	if program.rsHostname == "" {
-		program.plugin.SetState(plugin.UNKNOWN, "no reference DNS hostname specified")
+		program.plugin.SetState(plugin.StatusUnknown, "no reference DNS hostname specified")
 		return false
 	}
 	if program.rsPort < 1 || program.rsPort > 65535 {
-		program.plugin.SetState(plugin.UNKNOWN, "invalid reference DNS port number")
+		program.plugin.SetState(plugin.StatusUnknown, "invalid reference DNS port number")
 		return false
 	}
 	program.hostname = strings.ToLower(program.hostname)
@@ -180,12 +180,12 @@ func (program *checkProgram) RunCheck() {
 	cOk, cSerial := program.getSerial("checked", checkResponse)
 	rOk, rSerial := program.getSerial("reference", refResponse)
 	if !(cOk && rOk) {
-		program.plugin.SetState(plugin.UNKNOWN, "could not read serials")
+		program.plugin.SetState(plugin.StatusUnknown, "could not read serials")
 		return
 	}
 	if cSerial == rSerial {
-		program.plugin.SetState(plugin.OK, "serials match")
+		program.plugin.SetState(plugin.StatusOK, "serials match")
 	} else {
-		program.plugin.SetState(plugin.CRITICAL, "serials mismatch")
+		program.plugin.SetState(plugin.StatusCritical, "serials mismatch")
 	}
 }
diff --git a/pkg/plugin/plugin.go b/pkg/plugin/plugin.go
index c78a196..061b06f 100644
--- a/pkg/plugin/plugin.go
+++ b/pkg/plugin/plugin.go
@@ -26,7 +26,7 @@ type Plugin struct {
 func New(name string) *Plugin {
 	p := new(Plugin)
 	p.name = name
-	p.status = UNKNOWN
+	p.status = StatusUnknown
 	p.message = "no status set"
 	p.perfData = make(map[string]*perfdata.PerfData)
 	return p
diff --git a/pkg/plugin/status.go b/pkg/plugin/status.go
index b7db5a8..170f594 100644
--- a/pkg/plugin/status.go
+++ b/pkg/plugin/status.go
@@ -7,10 +7,10 @@ type Status int
 
 // Plugin exit statuses.
 const (
-	OK Status = iota
-	WARNING
-	CRITICAL
-	UNKNOWN
+	StatusOK Status = iota
+	StatusWarning
+	StatusCritical
+	StatusUnknown
 )
 
 // String representations of the plugin statuses.