diff --git a/src/cursed_hr/cursed_hr.py b/src/cursed_hr/cursed_hr.py
index 762579d36..5536fab43 100644
--- a/src/cursed_hr/cursed_hr.py
+++ b/src/cursed_hr/cursed_hr.py
@@ -20,7 +20,7 @@
 from copy import deepcopy
 from dataclasses import dataclass
 from datetime import datetime
-from enum import IntEnum
+from enum import IntEnum, unique
 from math import ceil
 from pathlib import Path
 from typing import Any, BinaryIO, Optional, Union
@@ -31,6 +31,7 @@
 from gallia.uds.core.service import NegativeResponse, UDSRequest, UDSResponse
 
 
+@unique
 class InterpretationColor(IntEnum):
     DEFAULT = 42
     UDS_REQUEST = 43
diff --git a/src/gallia/db/db_handler.py b/src/gallia/db/db_handler.py
index 0cdc763df..6cd59931d 100644
--- a/src/gallia/db/db_handler.py
+++ b/src/gallia/db/db_handler.py
@@ -5,7 +5,7 @@
 import asyncio
 import json
 from datetime import datetime
-from enum import Enum
+from enum import Enum, unique
 from pathlib import Path
 from typing import Any, Optional
 
@@ -118,6 +118,7 @@ def bytes_repr(data: bytes) -> str:
 """
 
 
+@unique
 class LogMode(Enum):
     implicit = "implicit"
     explicit = "explicit"
diff --git a/src/gallia/penlog.py b/src/gallia/penlog.py
index 2d6de5e56..898521758 100644
--- a/src/gallia/penlog.py
+++ b/src/gallia/penlog.py
@@ -2,12 +2,13 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-from enum import Enum
+from enum import Enum, unique
 from typing import Any, Optional
 
 import penlog
 
 
+@unique
 class MessageType(str, Enum):
     READ = "read"
     WRITE = "write"
diff --git a/src/gallia/transports/doip.py b/src/gallia/transports/doip.py
index d3300bd58..98070838d 100644
--- a/src/gallia/transports/doip.py
+++ b/src/gallia/transports/doip.py
@@ -7,24 +7,27 @@
 import asyncio
 import struct
 from dataclasses import dataclass
-from enum import IntEnum
+from enum import IntEnum, unique
 from typing import Optional, TypedDict, Union, cast
 
 from gallia.penlog import Logger
 from gallia.transports.base import BaseTransport, TargetURI, _int_spec
 
 
+@unique
 class ProtocolVersions(IntEnum):
     ISO_13400_2_2010 = 0x01
     ISO_13400_2_2012 = 0x02
 
 
+@unique
 class RoutingActivationRequestTypes(IntEnum):
     Default = 0x00
     WWH_OBD = 0x01
     CentralSecurity = 0xE0
 
 
+@unique
 class RoutingActivationResponseCodes(IntEnum):
     UnknownSourceAddress = 0x00
     NoRessources = 0x01
@@ -37,6 +40,7 @@ class RoutingActivationResponseCodes(IntEnum):
     SuccessConfirmationRequired = 0x11
 
 
+@unique
 class PayloadTypes(IntEnum):
     NegativeAcknowledge = 0x0000
     VehicleIdentificationRequestMessage = 0x0002
@@ -47,16 +51,18 @@ class PayloadTypes(IntEnum):
     AliveCheckRequest = 0x0007
     AliveCheckResponse = 0x0008
     DoIPEntityStatusRequest = 0x4001
-    DoIPEntityStatusResponse = 0x4001
+    DoIPEntityStatusResponse = 0x4002
     DiagnosticMessage = 0x8001
     DiagnosticMessagePositiveAcknowledgement = 0x8002
     DiagnosticMessageNegativeAcknowledgement = 0x8003
 
 
+@unique
 class DiagnosticMessagePositiveAckCodes(IntEnum):
     Success = 0x00
 
 
+@unique
 class DiagnosticMessageNegativeAckCodes(IntEnum):
     InvalidSourceAddress = 0x02
     UnknownTargetAddress = 0x03
@@ -67,6 +73,7 @@ class DiagnosticMessageNegativeAckCodes(IntEnum):
     TransportProtocolError = 0x08
 
 
+@unique
 class GenericHeaderNACKCodes(IntEnum):
     IncorrectPatternFormat = 0x01
     UnknownPayloadType = 0x02
diff --git a/src/gallia/uds/core/constants.py b/src/gallia/uds/core/constants.py
index bc7a1f3f1..aa5bfc99b 100644
--- a/src/gallia/uds/core/constants.py
+++ b/src/gallia/uds/core/constants.py
@@ -2,9 +2,10 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-from enum import IntEnum
+from enum import IntEnum, unique
 
 
+@unique
 class UDSIsoServices(IntEnum):
     ShowCurrentData = 0x01
     ShowFreezeFrameData = 0x02
@@ -46,6 +47,7 @@ class UDSIsoServices(IntEnum):
     NegativeResponse = 0x7F
 
 
+@unique
 class UDSErrorCodes(IntEnum):
     generalReject = 0x10
     serviceNotSupported = 0x11
@@ -56,7 +58,7 @@ class UDSErrorCodes(IntEnum):
     conditionsNotCorrect = 0x22
     requestSequenceError = 0x24
     noResponseFromSubnetComponent = 0x25
-    failurePreventsExecutionOfRequestedAction = 0x25
+    failurePreventsExecutionOfRequestedAction = 0x26
     requestOutOfRange = 0x31
     securityAccessDenied = 0x33
     authenticationRequired = 0x34
@@ -123,6 +125,7 @@ class UDSErrorCodes(IntEnum):
     vehicleManufacturerSpecificConditionsNotCorrectFE = 0xFE
 
 
+@unique
 class DSCSubFuncs(IntEnum):
     # defaultSession
     DS = 0x01
@@ -134,6 +137,7 @@ class DSCSubFuncs(IntEnum):
     SSDS = 0x04
 
 
+@unique
 class RCSubFuncs(IntEnum):
     # start routine
     STR = 0x01
@@ -143,6 +147,7 @@ class RCSubFuncs(IntEnum):
     RRR = 0x03
 
 
+@unique
 class CCSubFuncs(IntEnum):
     # enableRxAndTx
     ERXTX = 0x00
@@ -155,12 +160,14 @@ class CCSubFuncs(IntEnum):
     # Plus vendor specific stuff...
 
 
+@unique
 class CDTCSSubFuncs(IntEnum):
     ON = 0x01
     OFF = 0x02
     # Plus vendor specific stuff...
 
 
+@unique
 class RDTCISubFuncs(IntEnum):
     # reportNumberOfDTCByStatusMask
     RNODTCBSM = 0x01
@@ -190,6 +197,7 @@ class RDTCISubFuncs(IntEnum):
     RDTCWPS = 0x15
 
 
+@unique
 class ERSubFuncs(IntEnum):
     # hardReset
     HR = 0x01
@@ -203,6 +211,7 @@ class ERSubFuncs(IntEnum):
     DRPSD = 0x05
 
 
+@unique
 class InputOutputControlParameter(IntEnum):
     # returnControlToECU
     RCTECU = 0x00
@@ -214,6 +223,7 @@ class InputOutputControlParameter(IntEnum):
     STA = 0x03
 
 
+@unique
 class DTCFormatIdentifier(IntEnum):
     # ISO15031-6DTCFormat
     ISO_15031_6 = 0x00
@@ -256,5 +266,6 @@ class DTCFormatIdentifier(IntEnum):
 }
 
 
+@unique
 class DataIdentifier(IntEnum):
     ActiveDiagnosticSessionDataIdentifier = 0xF186
diff --git a/src/gallia/udscan/core.py b/src/gallia/udscan/core.py
index bc5bdd260..73fe9703f 100644
--- a/src/gallia/udscan/core.py
+++ b/src/gallia/udscan/core.py
@@ -14,7 +14,7 @@
 from argparse import ArgumentDefaultsHelpFormatter, Namespace
 from asyncio import Task
 from datetime import datetime, timezone
-from enum import Enum, IntEnum
+from enum import Enum, IntEnum, unique
 from importlib.metadata import EntryPoint, entry_points, version
 from pathlib import Path
 from secrets import token_urlsafe
@@ -37,6 +37,7 @@
 from gallia.utils import camel_to_snake, g_repr
 
 
+@unique
 class ExitCodes(IntEnum):
     SUCCESS = 0
     GENERIC_ERROR = 1
@@ -44,6 +45,7 @@ class ExitCodes(IntEnum):
     TEARDOWN_FAILED = 11
 
 
+@unique
 class FileNames(Enum):
     PROPERTIES_PRE = "PROPERTIES_PRE.json"
     PROPERTIES_POST = "PROPERTIES_POST.json"
diff --git a/src/penlog/__init__.py b/src/penlog/__init__.py
index bff4c5d7f..dd1b2aaec 100644
--- a/src/penlog/__init__.py
+++ b/src/penlog/__init__.py
@@ -11,14 +11,16 @@
 import uuid
 from dataclasses import dataclass, asdict
 from datetime import datetime
-from enum import Enum, IntEnum
+from enum import Enum, IntEnum, unique
 from typing import Any, TextIO, Optional
 
 
+@unique
 class MessageType(str, Enum):
     MESSAGE = "message"
 
 
+@unique
 class MessagePrio(IntEnum):
     EMERGENCY = 0
     ALERT = 1
@@ -31,6 +33,7 @@ class MessagePrio(IntEnum):
     TRACE = 8
 
 
+@unique
 class OutputType(Enum):
     JSON = "json"
     JSON_PRETTY = "json-pretty"
@@ -39,6 +42,7 @@ class OutputType(Enum):
     HR_NANO = "hr-nano"
 
 
+@unique
 class Color(Enum):
     NOP = ""
     RESET = "\033[0m"