diff --git a/cidr.go b/cidr.go
index f158844c..c68c7bc7 100644
--- a/cidr.go
+++ b/cidr.go
@@ -299,16 +299,21 @@ func IpAddresses(ipnet *net.IPNet) (ips chan string) {
 // IPToInteger converts an IP address to its integer representation.
 // It supports both IPv4 as well as IPv6 addresses.
 func IPToInteger(ip net.IP) (*big.Int, int, error) {
-	val := &big.Int{}
-	val.SetBytes([]byte(ip))
-
-	if len(ip) == net.IPv4len {
-		return val, 32, nil //nolint
-	} else if len(ip) == net.IPv6len {
-		return val, 128, nil //nolint
-	} else {
-		return nil, 0, fmt.Errorf("unsupported address length %d", len(ip))
+	val := new(big.Int)
+
+	// check if the ip is v4 => convert to 4 bytes representation
+	if ipv4 := ip.To4(); ipv4 != nil {
+		val.SetBytes(ipv4)
+		return val, 32, nil
+	}
+
+	// check if the ip is v6 => convert to 16 bytes representation
+	if ipv6 := ip.To16(); ipv6 != nil {
+		val.SetBytes(ipv6)
+		return val, 128, nil
 	}
+
+	return nil, 0, fmt.Errorf("unsupported IP address format")
 }
 
 // IntegerToIP converts an Integer IP address to net.IP format.
diff --git a/ip_test.go b/ip_test.go
index 289c4c3b..e8249112 100644
--- a/ip_test.go
+++ b/ip_test.go
@@ -30,9 +30,9 @@ func TestIpEncodings(t *testing.T) {
 	res = AlterIP(ip, []string{"4"}, 0, false)
 	require.True(t, sliceutil.ContainsItems(res, []string{"0x7f.0x0.0x0.0x1", "0x7f000001"}))
 	res = AlterIP(ip, []string{"5"}, 0, false)
-	require.Equal(t, []string{"281472812449793"}, res)
+	require.Equal(t, []string{"2130706433"}, res)
 	res = AlterIP(ip, []string{"6"}, 0, false)
-	require.Equal(t, []string{"111111111111111101111111000000000000000000000001"}, res)
+	require.Equal(t, []string{"1111111000000000000000000000001"}, res)
 	res = AlterIP(ip, []string{"7"}, 0, false)
 	require.Equal(t, []string{"0x7f.0.0.0x1"}, res)
 	res = AlterIP("2001:0db8:85a3:0000:0000:8a2e:0370:7334", []string{"8"}, 0, false)