diff --git a/StockServer/ServerSocket.cpp b/StockServer/ServerSocket.cpp
new file mode 100644
index 0000000..50ccf06
--- /dev/null
+++ b/StockServer/ServerSocket.cpp
@@ -0,0 +1,443 @@
+   #include "stdafx.h"
+#include "StockServer.h"
+
+#include "ServerSocket.h"
+#include "ClientSocket.h"
+#include "..\\Common\\ComData.h"
+
+#include "MainFrm.h"
+
+#ifdef _DEBUG
+#define new DEBUG_NEW
+#undef THIS_FILE
+static char THIS_FILE[] = __FILE__;
+#endif
+
+
+/////////////////////////////////////////////////////////////////////////////
+// CServerSocket
+
+CServerSocket::CServerSocket(CMainFrame* pMainFrame)
+{
+	ASSERT(pMainFrame);
+	m_pMainFrame = pMainFrame;
+	m_nMaxClients = -1;
+}
+
+CServerSocket::~CServerSocket()
+{
+	CloseClients();
+	UpdateClientsList();
+	Close();
+}
+
+
+// Do not edit the following lines, which are needed by ClassWizard.
+#if 0
+BEGIN_MESSAGE_MAP(CServerSocket, CSocket)
+	//{{AFX_MSG_MAP(CServerSocket)
+	//}}AFX_MSG_MAP
+END_MESSAGE_MAP()
+#endif	// 0
+
+/////////////////////////////////////////////////////////////////////////////
+// CListeningSocket member functions
+
+CPtrList* CServerSocket::GetClientsList()
+{
+	if (m_ClientstList.IsEmpty())
+		return NULL;
+	
+	return &m_ClientstList;
+}
+
+int CServerSocket::GetClientsConnectedCount()
+{
+	return m_ClientstList.GetCount(); 
+}
+
+int CServerSocket::GetTotalMessagesCount()
+{
+	int nMessageCount = 0;
+	int nCount = m_ClientstList.GetCount();
+	for (int i = 0; i < nCount; i++) {
+
+		sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+		ASSERT(pClientCom);
+
+		nMessageCount += pClientCom->szMessagesList.GetCount();  
+	}
+
+	return nMessageCount;
+}
+
+
+
+BOOL CServerSocket::BeginListening(UINT uPort, int nMaxClients)
+{
+	m_nMaxClients = nMaxClients;
+	
+	if(!m_ClientstList.IsEmpty())
+		CloseClients();
+
+	if (!Create(uPort))
+		return FALSE;
+
+	if (!Listen())
+		return FALSE;
+
+	return TRUE;
+}
+
+void CServerSocket::OnAccept(int nErrorCode) 
+{
+	CSocket::OnAccept(nErrorCode);
+
+	ProcessAccept();
+}
+
+//when got a connection message from a client
+void CServerSocket::ProcessAccept()
+{
+	CClientSocket* pClientSocket = new CClientSocket(this);
+	ASSERT(pClientSocket);
+
+	if (!Accept(*pClientSocket)) {
+		delete pClientSocket;
+		return;
+	}
+	pClientSocket->Init();
+
+	if (m_nMaxClients != -1) {
+		if (m_nMaxClients <= m_ClientstList.GetCount()) {
+			try {
+				//send the connection confirmation to the client,add to the list - yh
+				CComData ComData;
+				ComData.m_ComDataType = CComData::COM_CLOSE;
+				ComData.m_FromID = CString((LPCTSTR)IDS_COM_SERVER);
+				ComData.m_StringBody = "¼­¹öÀÇ ÃÖ´ëÁ¢¼Ó¼ö¸¦ ³Ñ¾ú½À´Ï´Ù.";
+				pClientSocket->SendCom(&ComData);
+				delete pClientSocket;
+
+				m_pMainFrame->AddMessage( ComData.m_FromID, ComData.m_StringBody );
+				return;
+			}
+			catch(CFileException* e){
+				TCHAR csError[CHAR_BUFFER_SIZE];
+				e->GetErrorMessage(csError, CHAR_BUFFER_SIZE);
+				AfxMessageBox(csError);
+			}
+		}
+	}
+
+	try {
+		//send the connection confirmation to the client,add to the list - yh
+		CComData ComData;
+		ComData.m_ComDataType = CComData::COM_SIGN_IN;
+		ComData.m_FromID = CString((LPCTSTR)IDS_COM_SERVER);
+
+		pClientSocket->SendCom(&ComData);
+	}
+	catch(CFileException* e){
+		TCHAR csError[CHAR_BUFFER_SIZE];
+		e->GetErrorMessage(csError, CHAR_BUFFER_SIZE);
+		AfxMessageBox(csError);
+	}
+
+	CString szIPAddress;
+	UINT	uPort;
+	pClientSocket->GetPeerName(szIPAddress, uPort);	
+
+	sClientComInfos* pClientCom = new sClientComInfos;
+	ASSERT(pClientCom);
+	
+	pClientCom->pSocket = (DWORD)pClientSocket;
+	pClientCom->strID = "";
+	pClientCom->szIPAddress = szIPAddress;
+	pClientCom->uPort = uPort;
+	pClientCom->TimeStarted = CTime::GetCurrentTime();
+
+	if(m_ClientstList.IsEmpty()){
+		m_ClientstList.AddHead(pClientCom);
+	}
+	else{
+		m_ClientstList.AddTail(pClientCom);
+	}
+}
+
+
+void CServerSocket::ProcessClientCom(CClientSocket* pClientSocket)
+{
+	ASSERT(pClientSocket);
+
+	try {
+
+		CComData ComData;
+		pClientSocket->ReceiveCom(&ComData);
+
+		if(ComData.m_ComDataType == CComData::COM_SIGN_IN) {
+
+			if(IsThisLoginBeingUsed(pClientSocket, &ComData)) {
+				try {
+					//send the connection confirmation to the client,add to the list - yh
+					ComData.Initialize();
+					ComData.m_ComDataType = CComData::COM_CLOSE;
+					ComData.m_FromID = CString((LPCTSTR)IDS_COM_SERVER);
+					ComData.m_StringBody = "Á¢¼ÓÁ¦ÇÑ ¼ö¸¦ ³Ñ¾ú½À´Ï´Ù.";
+					pClientSocket->SendCom(&ComData);
+				}
+				catch(CFileException* e) {
+					TCHAR csError[CHAR_BUFFER_SIZE];
+					e->GetErrorMessage(csError, CHAR_BUFFER_SIZE);
+					AfxMessageBox(csError);
+				}
+				
+				RemoveClient(pClientSocket);
+				return;
+			}
+			
+			SendSignChange( pClientSocket, ComData.m_StringBody );
+
+			UpdateClientsList();
+
+			m_pMainFrame->AddMessage(ComData.m_StringBody, "Client Sign in." );
+		}
+		else if(ComData.m_ComDataType == CComData::COM_SIGN_OUT) {
+			RemoveClient(pClientSocket);
+			UpdateClientsList();
+			m_pMainFrame->AddMessage(ComData.m_FromID, "Client Sign out." );
+		}
+		else if(ComData.m_ComDataType == CComData::COM_MESSAGE) {
+
+			m_pMainFrame->AddMessage(ComData.m_FromID, ComData.m_StringBody );
+			UpdateClientsInfo(&ComData, pClientSocket);
+		}
+	}
+	catch(CFileException* e) {
+		TCHAR csError[CHAR_BUFFER_SIZE];
+		e->GetErrorMessage(csError, CHAR_BUFFER_SIZE);
+		AfxMessageBox(csError);
+	}
+}
+
+void CServerSocket::SendSignChange(CClientSocket* pClientSocket, CString strNewId)
+{
+	int nCount = m_ClientstList.GetCount();
+	for (int i = 0; i < nCount; i++) {
+		sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+		ASSERT(pClientCom);
+		CClientSocket* pClientSocketTmp = (CClientSocket*)pClientCom->pSocket;
+		ASSERT(pClientSocketTmp);
+
+		if(pClientSocket == pClientSocketTmp)
+		{
+			pClientCom->strID = strNewId; // ¼­¹ö¿¡¼­ Ŭ¶óÀ̾ðÆ® ¸®½ºÆ®ÀÇ Á¢¼ÓIDÈ®Á¤ÇÔ.
+
+			CComData ComData;
+			ComData.m_ComDataType = CComData::COM_SIGN_CHANGE;
+			ComData.m_FromID = CString((LPCTSTR)IDS_COM_SERVER);
+			ComData.m_StringBody = strNewId;
+
+			pClientSocket->SendCom(&ComData);
+			return ;
+		}
+	}
+}
+
+BOOL CServerSocket::CheckAlive(CClientSocket* pClientSocket, int nCheck)
+{
+	CComData ComData;
+	ComData.m_ComDataType = CComData::COM_CHECKALIVE;
+	ComData.m_FromID = CString((LPCTSTR)IDS_COM_SERVER);
+
+	while( nCheck-- )
+	{
+		if( pClientSocket->SendCom(&ComData) == FALSE )
+		{
+			RemoveClient(pClientSocket);
+			return FALSE;
+		}
+	}
+	return TRUE;
+}
+
+BOOL CServerSocket::IsThisLoginBeingUsed(CClientSocket* pClientSocket, CComData* pComData)
+{
+	ASSERT(pClientSocket);
+
+	CString strCheckID = pComData->m_FromID;
+
+	if(strCheckID == CString((LPCTSTR)IDS_COM_SERVER))
+		return TRUE; // this name is used by server only!
+	
+	if(m_ClientstList.IsEmpty()) return TRUE;
+
+	int nCount = m_ClientstList.GetCount();
+	int nCheckCount = 0;
+	while(nCheckCount++ < 2) { // °°ÀºIDÀÏ°æ¿ì 2°³±îÁö¸¸ Çã¿ëÇÔ.
+		
+		BOOL bStop = TRUE;
+
+		for (int i = 0; i < nCount; i++) {
+			sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+			ASSERT(pClientCom);
+			CClientSocket* pClientSocketTmp = (CClientSocket*)pClientCom->pSocket;
+			ASSERT(pClientSocketTmp);
+
+			if(strCheckID == pClientCom->strID &&
+			   pClientSocket != pClientSocketTmp)
+			{
+				if( !CheckAlive(pClientSocketTmp) ) 
+				{
+					pComData->m_StringBody = strCheckID;
+					return FALSE;
+				}
+
+				strCheckID.Format("%s(%dth)", pComData->m_FromID, nCheckCount);
+				bStop = FALSE;
+				break;
+			}
+		}
+
+		if( bStop ) {
+			pComData->m_StringBody = strCheckID;
+			return FALSE;
+		}
+	}
+
+	return TRUE;
+}
+
+void CServerSocket::UpdateClientsList()
+{
+	m_pMainFrame->UpdateClientsList(&m_ClientstList);
+}
+
+void CServerSocket::UpdateClientsInfo(CComData* pComData, CClientSocket* pClientSocket)
+{
+	ASSERT(pComData);	
+	
+	int nCount = m_ClientstList.GetCount();
+	for (int i = 0; i < nCount; i++) {
+
+		sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+		ASSERT(pClientCom);
+		CClientSocket* pClientSocketTmp = (CClientSocket*)pClientCom->pSocket;
+		ASSERT(pClientSocketTmp);
+
+		if (pClientSocket == pClientSocketTmp) {
+
+			CString szBuf;
+			szBuf.Format("%s;%s", GlobalHelper::GetLocalTime(), pComData->m_StringBody); 
+			if (pClientCom->szMessagesList.IsEmpty())
+				pClientCom->szMessagesList.AddHead(szBuf);
+			else
+				pClientCom->szMessagesList.AddTail(szBuf);
+			return;
+		}
+	}
+}
+
+void CServerSocket::RemoveClient(CClientSocket* pClientSocket)
+{
+	ASSERT(pClientSocket);
+	
+	int nCount = m_ClientstList.GetCount();
+	for (int i = 0; i < nCount; i++) {
+
+		sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+		ASSERT(pClientCom);
+		CClientSocket* pClientSocketTmp = (CClientSocket*)pClientCom->pSocket;
+		ASSERT(pClientSocketTmp);
+		
+		if(pClientSocket == pClientSocketTmp) {
+
+			m_ClientstList.RemoveAt(m_ClientstList.FindIndex(i));
+
+			pClientSocketTmp->Close();
+			delete pClientSocketTmp;
+			pClientSocketTmp = NULL;
+
+			pClientCom->szMessagesList.RemoveAll();  
+			delete pClientCom;
+			pClientCom = NULL;
+			return;
+		}
+	}
+}
+
+void CServerSocket::CloseClients()
+{
+	int nCount = m_ClientstList.GetCount();
+	for (int i = 0; i < nCount; i++) {
+
+		sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+		ASSERT(pClientCom);
+		CClientSocket* pClientSocketTmp = (CClientSocket*)pClientCom->pSocket;
+		ASSERT(pClientSocketTmp);
+
+		try {
+			//send the connection confirmation to the client,add to the list - yh
+			CComData ComData;
+			ComData.m_ComDataType = CComData::COM_CLOSE;
+			ComData.m_FromID = CString((LPCTSTR)IDS_COM_SERVER);
+			ComData.m_StringBody = "¿¬°áÁ¾·áÇÕ´Ï´Ù.";
+
+			pClientSocketTmp->SendCom(&ComData);
+		}
+		catch(CFileException* e) {
+			TCHAR csError[CHAR_BUFFER_SIZE];
+			e->GetErrorMessage(csError, CHAR_BUFFER_SIZE);
+			AfxMessageBox(csError);
+		}
+
+		pClientSocketTmp->Close();
+		delete pClientSocketTmp;
+		pClientSocketTmp = NULL;
+
+		m_pMainFrame->AddMessage(pClientCom->strID, "¿¬°áÁ¾·áÇÕ´Ï´Ù.");
+			
+		pClientCom->szMessagesList.RemoveAll();  
+		delete pClientCom;
+		pClientCom = NULL;
+	}
+
+	m_ClientstList.RemoveAll();
+}
+
+void CServerSocket::SendMessageTo(CString szClient, CString szMessage)
+{
+/*	int nCount = m_ClientstList.GetCount();
+	for (int i = 0; i < nCount; i++) {
+
+		sClientComInfos* pClientCom = (sClientComInfos*)m_ClientstList.GetAt(m_ClientstList.FindIndex(i));
+		ASSERT(pClientCom);
+		CComData* pComDataTmp = (CComData*)&pClientCom->ComData;
+		ASSERT(pComDataTmp);
+		CClientSocket* pClientSocketTmp = (CClientSocket*)pComDataTmp->pSocket;
+		ASSERT(pClientSocketTmp);
+
+		if (pComDataTmp->szFrom == szClient) {
+
+			try {
+				//send the connection confirmation to the client,add to the list - yh
+				CComData ComDataTmp;
+				ComDataTmp.szFrom	 = CString((LPCTSTR)IDS_COM_SERVER);
+				ComDataTmp.uSignIcon = SERVER_ICON;
+				ComDataTmp.szMessage = szMessage;
+				ComDataTmp.uMessage  = CComData::COM_PRIVATE_MESSAGE;
+				pClientSocketTmp->SendCom(&ComDataTmp);
+			}
+			catch(CFileException* e) {
+				TCHAR csError[CHAR_BUFFER_SIZE];
+				e->GetErrorMessage(csError, CHAR_BUFFER_SIZE);
+				AfxMessageBox(csError);
+			}
+
+			return;
+		}
+	}
+*/
+}
+
+