diff --git a/src/init.cpp b/src/init.cpp
index 09eb76eaeeb..3ab62638133 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1042,16 +1042,17 @@ bool AppInitParameterInteraction(const ArgsManager& args)
 
     // Trim requested connection counts, to fit into system limitations
     // <int> in std::min<int>(...) to work around FreeBSD compilation issue described in #2695
-    nFD = RaiseFileDescriptorLimit(nMaxConnections + MIN_CORE_FILEDESCRIPTORS + MAX_ADDNODE_CONNECTIONS + nBind);
+    nFD = RaiseFileDescriptorLimit(nMaxConnections + MIN_CORE_FILEDESCRIPTORS + MAX_ADDNODE_CONNECTIONS + nBind + NUM_FDS_MESSAGE_CAPTURE);
+
 #ifdef USE_POLL
     int fd_max = nFD;
 #else
     int fd_max = FD_SETSIZE;
 #endif
-    nMaxConnections = std::max(std::min<int>(nMaxConnections, fd_max - nBind - MIN_CORE_FILEDESCRIPTORS - MAX_ADDNODE_CONNECTIONS), 0);
+    nMaxConnections = std::max(std::min<int>(nMaxConnections, fd_max - nBind - MIN_CORE_FILEDESCRIPTORS - MAX_ADDNODE_CONNECTIONS - NUM_FDS_MESSAGE_CAPTURE), 0);
     if (nFD < MIN_CORE_FILEDESCRIPTORS)
         return InitError(_("Not enough file descriptors available."));
-    nMaxConnections = std::min(nFD - MIN_CORE_FILEDESCRIPTORS - MAX_ADDNODE_CONNECTIONS, nMaxConnections);
+    nMaxConnections = std::min(nFD - MIN_CORE_FILEDESCRIPTORS - MAX_ADDNODE_CONNECTIONS - NUM_FDS_MESSAGE_CAPTURE, nMaxConnections);
 
     if (nMaxConnections < nUserMaxConnections)
         InitWarning(strprintf(_("Reducing -maxconnections from %d to %d, because of system limitations."), nUserMaxConnections, nMaxConnections));
diff --git a/src/net.cpp b/src/net.cpp
index a3f7f3aba1d..29529d54caa 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -2929,3 +2929,31 @@ uint64_t CConnman::CalculateKeyedNetGroup(const CAddress& ad) const
 
     return GetDeterministicRandomizer(RANDOMIZER_ID_NETGROUP).Write(vchNetGroup.data(), vchNetGroup.size()).Finalize();
 }
+
+void CaptureMessage(const CAddress& addr, const std::string& msg_type, const Span<const unsigned char>& data, bool is_incoming)
+{
+    // Note: This function captures the message at the time of processing,
+    // not at socket receive/send time.
+    // This ensures that the messages are always in order from an application
+    // layer (processing) perspective.
+    auto now = GetTime<std::chrono::microseconds>();
+
+    // Windows folder names can not include a colon
+    std::string clean_addr = addr.ToString();
+    std::replace(clean_addr.begin(), clean_addr.end(), ':', '_');
+
+    fs::path base_path = GetDataDir() / "message_capture" / clean_addr;
+    fs::create_directories(base_path);
+
+    fs::path path = base_path / (is_incoming ? "msgs_recv.dat" : "msgs_sent.dat");
+    CAutoFile f(fsbridge::fopen(path, "ab"), SER_DISK, CLIENT_VERSION);
+
+    ser_writedata64(f, now.count());
+    f.write(msg_type.data(), msg_type.length());
+    for (auto i = msg_type.length(); i < CMessageHeader::COMMAND_SIZE; ++i) {
+        f << '\0';
+    }
+    uint32_t size = data.size();
+    ser_writedata32(f, size);
+    f.write((const char*)data.data(), data.size());
+}
diff --git a/src/net.h b/src/net.h
index 087135a290d..96d411bf291 100644
--- a/src/net.h
+++ b/src/net.h
@@ -20,6 +20,7 @@
 #include <policy/feerate.h>
 #include <protocol.h>
 #include <random.h>
+#include <span.h>
 #include <streams.h>
 #include <sync.h>
 #include <threadinterrupt.h>
@@ -75,6 +76,8 @@ static constexpr uint64_t DEFAULT_MAX_UPLOAD_TARGET = 0;
 static const bool DEFAULT_BLOCKSONLY = false;
 /** -peertimeout default */
 static const int64_t DEFAULT_PEER_CONNECT_TIMEOUT = 60;
+/** Number of file descriptors required for message capture **/
+static const int NUM_FDS_MESSAGE_CAPTURE = 1;
 
 static const bool DEFAULT_FORCEDNSSEED = false;
 static const size_t DEFAULT_MAXRECEIVEBUFFER = 5 * 1000;
@@ -1239,6 +1242,9 @@ inline std::chrono::microseconds PoissonNextSend(std::chrono::microseconds now,
     return std::chrono::microseconds{PoissonNextSend(now.count(), average_interval.count())};
 }
 
+/** Dump binary message to file, with timestamp */
+void CaptureMessage(const CAddress& addr, const std::string& msg_type, const Span<const unsigned char>& data, bool is_incoming);
+
 struct NodeEvictionCandidate
 {
     NodeId id;