diff --git a/CHANGELOG.md b/CHANGELOG.md
index e848640298a..f26cd9ea24a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## [1.7.0] - Unreleased
 
 - Added: [#5537](https://github.com/ethereum/aleth/pull/5537) Creating Ethereum Node Record (ENR) at program start.
+- Changed: [#5559](https://github.com/ethereum/aleth/pull/5559) Update peer validation error messages.
 
 [1.6.0]: https://github.com/ethereum/aleth/compare/v1.6.0-alpha.1...master
 
@@ -24,4 +25,4 @@
 - Fixed: [#5547](https://github.com/ethereum/aleth/pull/5547) Fix unnecessary slow-down of eth_flush RPC method.
 
 [1.6.0]: https://github.com/ethereum/aleth/compare/v1.6.0-alpha.1...release/1.6
-[1.7.0]: https://github.com/ethereum/aleth/compare/release/1.6...master
\ No newline at end of file
+[1.7.0]: https://github.com/ethereum/aleth/compare/release/1.6...master
diff --git a/libethereum/EthereumPeer.cpp b/libethereum/EthereumPeer.cpp
index f673e66c854..f3738fee042 100644
--- a/libethereum/EthereumPeer.cpp
+++ b/libethereum/EthereumPeer.cpp
@@ -1,19 +1,6 @@
-/*
-    This file is part of cpp-ethereum.
-
-    cpp-ethereum is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    cpp-ethereum is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
-*/
+// Aleth: Ethereum C++ client, tools and libraries.
+// Copyright 2019 Aleth Authors.
+// Licensed under the GNU General Public License, Version 3.
 
 #include "EthereumPeer.h"
 #include <libethcore/Common.h>
@@ -24,10 +11,10 @@ using namespace std;
 using namespace dev;
 using namespace dev::eth;
 
-static std::string const c_ethCapability = "eth";
-
 namespace
 {
+std::string const c_ethCapability = "eth";
+
 string toString(Asking _a)
 {
     switch (_a)
@@ -67,17 +54,20 @@ void EthereumPeer::setStatus(unsigned _protocolVersion, u256 const& _networkId,
 std::string EthereumPeer::validate(
     h256 const& _hostGenesisHash, unsigned _hostProtocolVersion, u256 const& _hostNetworkId) const
 {
-    std::string error;
-    if (m_genesisHash != _hostGenesisHash)
-        error = "Invalid genesis hash.";
+    std::stringstream error;
+    if (m_networkId != _hostNetworkId)
+        error << "Network identifier mismatch. Host network id: " << _hostNetworkId
+              << ", peer network id: " << m_networkId;
     else if (m_protocolVersion != _hostProtocolVersion)
-        error = "Invalid protocol version.";
-    else if (m_networkId != _hostNetworkId)
-        error = "Invalid network identifier.";
+        error << "Protocol version mismatch. Host protocol version: " << _hostProtocolVersion
+              << ", peer protocol version: " << m_protocolVersion;
+    else if (m_genesisHash != _hostGenesisHash)
+        error << "Genesis hash mismatch. Host genesis hash: " << _hostGenesisHash
+              << ", peer genesis hash: " << m_genesisHash;
     else if (m_asking != Asking::State && m_asking != Asking::Nothing)
-        error = "Peer banned for unexpected status message.";
+        error << "Peer banned for unexpected status message.";
 
-    return error;
+    return error.str();
 }
 
 void EthereumPeer::requestStatus(