diff --git a/config/krb5conf.go b/config/krb5conf.go
index 47ca956b..9993bb99 100644
--- a/config/krb5conf.go
+++ b/config/krb5conf.go
@@ -555,24 +555,38 @@ func parseETypes(s []string, w bool) []int {
 // Parse a time duration string in the configuration to a golang time.Duration.
 func parseDuration(s string) (time.Duration, error) {
 	s = strings.Replace(s, " ", "", -1)
+
+	// handle Nd[NmNs]
 	if strings.Contains(s, "d") {
-		s = strings.Replace(s, "d", "", -1)
-		// assume this is a round number for days...
-		days, err := strconv.ParseInt(s, 10, 32)
+		ds := strings.SplitN(s, "d", 2)
+		dn, err := strconv.ParseUint(ds[0], 10, 32)
 		if err != nil {
-			return time.Duration(0), errors.New("Invalid time duration.")
+			return time.Duration(0), errors.New("invalid time duration.")
+		}
+		d := time.Duration(dn*24) * time.Hour
+		if ds[1] != "" {
+			dp, err := time.ParseDuration(ds[1])
+			if err != nil {
+				return time.Duration(0), errors.New("invalid time duration.")
+			}
+			d = d + dp
 		}
-		var secs = int(days) * 86400
-		s = strconv.Itoa(secs)
+		return d, nil
 	}
+
+	// handle Nm[Ns]
 	d, err := time.ParseDuration(s)
 	if err == nil {
 		return d, nil
 	}
+
+	// handle N
 	v, err := strconv.ParseUint(s, 10, 32)
 	if err == nil && v > 0 {
 		return time.Duration(v) * time.Second, nil
 	}
+
+	// handle h:m[:s]
 	if strings.Contains(s, ":") {
 		t := strings.Split(s, ":")
 		if 2 > len(t) || len(t) > 3 {
diff --git a/config/krb5conf_test.go b/config/krb5conf_test.go
index 047dc29c..0b2160ae 100644
--- a/config/krb5conf_test.go
+++ b/config/krb5conf_test.go
@@ -99,3 +99,31 @@ func TestLoad(t *testing.T) {
 	assert.Equal(t, "TEST.GOKRB5", c.DomainRealm["test.gokrb5"], "Domain to realm mapping not as expected")
 
 }
+
+func TestParseDuration(t *testing.T) {
+	// https://web.mit.edu/kerberos/krb5-1.12/doc/basic/date_format.html#duration
+	hms, _ := time.ParseDuration("12h30m15s")
+	hm, _ := time.ParseDuration("12h30m")
+	h, _ := time.ParseDuration("12h")
+	var tests = []struct {
+		timeStr  string
+		duration time.Duration
+	}{
+		{"100", time.Duration(100) * time.Second},
+		{"12:30", hm},
+		{"12:30:15", hms},
+		{"1d12h30m15s", time.Duration(24)*time.Hour + hms},
+		{"1d12h30m", time.Duration(24)*time.Hour + hm},
+		{"1d12h", time.Duration(24)*time.Hour + h},
+		{"1d", time.Duration(24) * time.Hour},
+	}
+	for _, test := range tests {
+		d, err := parseDuration(test.timeStr)
+		if err != nil {
+			t.Errorf("Error parsing %s: %v", test.timeStr, err)
+		}
+		assert.Equal(t, test.duration, d, "Duration not as expected for: "+test.timeStr)
+
+	}
+
+}