diff --git a/data/include/join/pack.hpp b/data/include/join/pack.hpp
index 466111dd..d5dab45f 100644
--- a/data/include/join/pack.hpp
+++ b/data/include/join/pack.hpp
@@ -52,17 +52,27 @@ namespace join
     static_assert (std::numeric_limits<float>::is_iec559 && std::numeric_limits<double>::is_iec559,
                    "MessagePack requires IEEE 754 floating point numbers");
 
+    /**
+     * @brief MessagePack serialization mode.
+     */
+    enum class PackWriteMode
+    {
+        None,             /**< no write mode set. */
+        ValidateEncoding, /**< validate UTF-8 encoding of strings. */
+    };
+
     /**
      * @brief message pack writer class.
      */
-    class PackWriter
+    template <PackWriteMode WriteMode = PackWriteMode::None>
+    class BasicPackWriter
     {
     public:
         /**
          * @brief create instance.
          * @param document MessagePack document to create.
          */
-        explicit PackWriter (std::ostream& document)
+        explicit BasicPackWriter (std::ostream& document)
         : _out (document.rdbuf ())
         {
         }
@@ -71,32 +81,32 @@ namespace join
          * @brief copy constructor.
          * @param other object to copy.
          */
-        PackWriter (const PackWriter& other) = delete;
+        BasicPackWriter (const BasicPackWriter& other) = delete;
 
         /**
          * @brief copy assignment.
          * @param other object to copy.
          * @return a reference of the current object.
          */
-        PackWriter& operator= (const PackWriter& other) = delete;
+        BasicPackWriter& operator= (const BasicPackWriter& other) = delete;
 
         /**
          * @brief move constructor.
          * @param other object to move.
          */
-        PackWriter (PackWriter&& other) = delete;
+        BasicPackWriter (BasicPackWriter&& other) = delete;
 
         /**
          * @brief move assignment.
          * @param other object to move.
          * @return a reference of the current object.
          */
-        PackWriter& operator= (PackWriter&& other) = delete;
+        BasicPackWriter& operator= (BasicPackWriter&& other) = delete;
 
         /**
          * @brief destroy instance.
          */
-        ~PackWriter () = default;
+        ~BasicPackWriter () = default;
 
         /**
          * @brief set null value.
@@ -322,6 +332,23 @@ namespace join
          */
         int setString (std::string_view value)
         {
+            if (JOIN_UNLIKELY (value.size () > std::numeric_limits<uint32_t>::max ()))
+            {
+                join::lastError = make_error_code (SaxErrc::InvalidValue);
+                reset ();
+                return -1;
+            }
+
+            if constexpr (WriteMode == PackWriteMode::ValidateEncoding)
+            {
+                if (JOIN_UNLIKELY (utf8::validate (value.data (), value.data () + value.size ()) == -1))
+                {
+                    join::lastError = make_error_code (SaxErrc::InvalidEncoding);
+                    reset ();
+                    return -1;
+                }
+            }
+
             if (value.size () < 32)
             {
                 append (static_cast<char> (0xa0 | value.size ()));
@@ -354,6 +381,13 @@ namespace join
          */
         int setBinary (std::span<const uint8_t> value, std::optional<int8_t> subtype = std::nullopt)
         {
+            if (JOIN_UNLIKELY (value.size () > std::numeric_limits<uint32_t>::max ()))
+            {
+                join::lastError = make_error_code (SaxErrc::InvalidValue);
+                reset ();
+                return -1;
+            }
+
             if (subtype)
             {
                 switch (value.size ())
@@ -697,6 +731,9 @@ namespace join
         size_t _depth = 0;
     };
 
+    /// MessagePack writer.
+    using PackWriter = BasicPackWriter<PackWriteMode::None>;
+
     /**
      * @brief MessagePack deserialization mode.
      */
diff --git a/data/tests/pack_writer_test.cpp b/data/tests/pack_writer_test.cpp
index a4f66194..4cf14e7c 100644
--- a/data/tests/pack_writer_test.cpp
+++ b/data/tests/pack_writer_test.cpp
@@ -429,6 +429,27 @@ TEST (PackWriter, setString)
     stream.str ("");
     EXPECT_EQ (packWriter.setString (std::string (65536, 'x')), 0);
     EXPECT_EQ (stream.str ().compare (0, 6, std::string ({'\xDB', '\x00', '\x01', '\x00', '\x00', '\x78'})), 0);
+
+    char dummy = 0;
+    stream.str ("");
+    EXPECT_EQ (packWriter.setString (std::string_view (&dummy, 1ULL << 32)), -1);
+    EXPECT_EQ (join::lastError, SaxErrc::InvalidValue);
+    EXPECT_TRUE (stream.str ().empty ());
+
+    stream.str ("");
+    EXPECT_EQ (packWriter.setString ("\xff"), 0);
+    EXPECT_EQ (stream.str (), std::string ({'\xA1', '\xFF'}));
+
+    join::BasicPackWriter<join::PackWriteMode::ValidateEncoding> validator (stream);
+
+    stream.str ("");
+    EXPECT_EQ (validator.setString ("\xc3\xa9"), 0);
+    EXPECT_EQ (stream.str (), std::string ({'\xA2', '\xC3', '\xA9'}));
+
+    stream.str ("");
+    EXPECT_EQ (validator.setString ("\xff"), -1);
+    EXPECT_EQ (join::lastError, SaxErrc::InvalidEncoding);
+    EXPECT_TRUE (stream.str ().empty ());
 }
 
 /**
@@ -474,6 +495,12 @@ TEST (PackWriter, setBinary)
     EXPECT_EQ (ext (256), std::string ({'\xC8', '\x01', '\x00', '\xFF'}));
     EXPECT_EQ (ext (65535), std::string ({'\xC8', '\xFF', '\xFF', '\xFF'}));
     EXPECT_EQ (ext (65536), std::string ({'\xC9', '\x00', '\x01', '\x00', '\x00', '\xFF'}));
+
+    uint8_t dummy = 0;
+    stream.str ("");
+    EXPECT_EQ (packWriter.setBinary (std::span<const uint8_t> (&dummy, 1ULL << 32)), -1);
+    EXPECT_EQ (join::lastError, SaxErrc::InvalidValue);
+    EXPECT_TRUE (stream.str ().empty ());
 }
 
 /**
@@ -673,6 +700,13 @@ TEST (PackWriter, setKey)
 
     EXPECT_EQ (key (std::span<const uint8_t> (bytes, sizeof (bytes)), -1), 0);
     EXPECT_EQ (stream.str ().substr (1), std::string ({'\xD5', '\xFF', '\x00', '\xFF'}));
+
+    join::BasicPackWriter<join::PackWriteMode::ValidateEncoding> validator (stream);
+    stream.str ("");
+    validator.startObject (1);
+    EXPECT_EQ (validator.setKey (std::string_view ("\xff")), -1);
+    EXPECT_EQ (join::lastError, SaxErrc::InvalidEncoding);
+    EXPECT_TRUE (stream.str ().empty ());
 }
 
 /**
diff --git a/fabric/tests/dns_test.cpp b/fabric/tests/dns_test.cpp
index c6a74781..29d94211 100644
--- a/fabric/tests/dns_test.cpp
+++ b/fabric/tests/dns_test.cpp
@@ -329,7 +329,7 @@ TEST_F (DnsTest, resolveAllName)
     aliases = Dns::Resolver::lookupAllName ("::");
     EXPECT_EQ (aliases.size (), 0);
 
-    aliases = Dns::Resolver::lookupAllName ("192.168.24.32");
+    aliases = Dns::Resolver::lookupAllName ("192.0.2.32");
     EXPECT_EQ (aliases.size (), 0);
 
     aliases = _resolver->resolveAllName ("127.0.0.1");
@@ -380,7 +380,7 @@ TEST_F (DnsTest, resolveName)
     alias = Dns::Resolver::lookupName ("::");
     EXPECT_TRUE (alias.empty ());
 
-    alias = Dns::Resolver::lookupName ("192.168.24.32");
+    alias = Dns::Resolver::lookupName ("192.0.2.32");
     EXPECT_TRUE (alias.empty ());
 
     alias = _resolver->resolveName ("127.0.0.1");