diff --git a/ChangeLog b/ChangeLog
index fff4b2a7..141f3b5c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2008-05-17  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
+
+	Don't add closed socket to DownloadEngine::addSocketForReadCheck()
+	* src/AbstractCommand.cc
+	* src/AbstractCommand.h
+	* src/ActivePeerConnectionCommand.cc
+	* src/FtpInitiateConnectionCommand.cc
+	* src/HttpInitiateConnectionCommand.cc
+	* src/InitiateConnectionCommandFactory.cc
+	* src/PeerAbstractCommand.cc
+	* src/PeerAbstractCommand.h
+	* src/PeerInitiateConnectionCommand.cc
+	* src/TrackerWatcherCommand.cc
+
 2008-05-17  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
 
 	Sort RequestSlot in ascending order and manipulate them using
diff --git a/src/AbstractCommand.cc b/src/AbstractCommand.cc
index 024e67c6..e9f16e73 100644
--- a/src/AbstractCommand.cc
+++ b/src/AbstractCommand.cc
@@ -58,8 +58,6 @@
 
 namespace aria2 {
 
-// TODO $$$$$$$$$$$ fix two nearly identical constructor. $$$$$$$$$$$$$$
-// Modify two constructor at the same time!
 AbstractCommand::AbstractCommand(int32_t cuid,
 				 const SharedHandle<Request>& req,
 				 RequestGroup* requestGroup,
@@ -69,22 +67,10 @@ AbstractCommand::AbstractCommand(int32_t cuid,
   req(req), e(e), socket(s),
   checkSocketIsReadable(false), checkSocketIsWritable(false),
   nameResolverCheck(false)
-{ 
-  setReadCheckSocket(socket);
-  timeout = this->e->option->getAsInt(PREF_TIMEOUT);
-  _requestGroup->increaseStreamConnection();
-}
-
-AbstractCommand::AbstractCommand(int32_t cuid,
-				 const SharedHandle<Request>& req,
-				 RequestGroup* requestGroup,
-				 DownloadEngine* e):
-  Command(cuid), RequestGroupAware(requestGroup),
-  req(req), e(e), socket(new SocketCore()),
-  checkSocketIsReadable(false), checkSocketIsWritable(false),
-  nameResolverCheck(false)
-{ 
-  setReadCheckSocket(socket);
+{
+  if(!socket.isNull() && socket->isOpen()) {
+    setReadCheckSocket(socket);
+  }
   timeout = this->e->option->getAsInt(PREF_TIMEOUT);
   _requestGroup->increaseStreamConnection();
 }
diff --git a/src/AbstractCommand.h b/src/AbstractCommand.h
index 45151ef6..ce27e3c1 100644
--- a/src/AbstractCommand.h
+++ b/src/AbstractCommand.h
@@ -106,10 +106,7 @@ private:
 public:
   AbstractCommand(int32_t cuid, const SharedHandle<Request>& req,
 		  RequestGroup* requestGroup, DownloadEngine* e,
-		  const SharedHandle<SocketCore>& s);
-
-  AbstractCommand(int32_t cuid, const SharedHandle<Request>& req,
-		  RequestGroup* requestGroup, DownloadEngine* e);
+		  const SharedHandle<SocketCore>& s = SharedHandle<SocketCore>());
 
   virtual ~AbstractCommand();
   bool execute();
diff --git a/src/ActivePeerConnectionCommand.cc b/src/ActivePeerConnectionCommand.cc
index 21bb9a64..a1249d91 100644
--- a/src/ActivePeerConnectionCommand.cc
+++ b/src/ActivePeerConnectionCommand.cc
@@ -46,6 +46,7 @@
 #include "prefs.h"
 #include "Option.h"
 #include "BtConstants.h"
+#include "SocketCore.h"
 
 namespace aria2 {
 
diff --git a/src/FtpInitiateConnectionCommand.cc b/src/FtpInitiateConnectionCommand.cc
index e5a94d56..e1598efa 100644
--- a/src/FtpInitiateConnectionCommand.cc
+++ b/src/FtpInitiateConnectionCommand.cc
@@ -67,6 +67,7 @@ Command* FtpInitiateConnectionCommand::createNextCommand
     logger->info(MSG_CONNECTING_TO_SERVER, cuid,
 		 e->option->get(PREF_HTTP_PROXY_HOST).c_str(),
 		 e->option->getAsInt(PREF_HTTP_PROXY_PORT));
+    socket.reset(new SocketCore());
     socket->establishConnection(resolvedAddresses.front(),
 				e->option->getAsInt(PREF_HTTP_PROXY_PORT));
     
@@ -86,6 +87,7 @@ Command* FtpInitiateConnectionCommand::createNextCommand
 
       logger->info(MSG_CONNECTING_TO_SERVER, cuid, req->getHost().c_str(),
 		   req->getPort());
+      socket.reset(new SocketCore());
       socket->establishConnection(resolvedAddresses.front(), req->getPort());
       command = new FtpNegotiationCommand(cuid, req, _requestGroup, e, socket);
     } else {
diff --git a/src/HttpInitiateConnectionCommand.cc b/src/HttpInitiateConnectionCommand.cc
index 76400187..84d8c6d6 100644
--- a/src/HttpInitiateConnectionCommand.cc
+++ b/src/HttpInitiateConnectionCommand.cc
@@ -66,6 +66,7 @@ Command* HttpInitiateConnectionCommand::createNextCommand
     logger->info(MSG_CONNECTING_TO_SERVER, cuid,
 		 e->option->get(PREF_HTTP_PROXY_HOST).c_str(),
 		 e->option->getAsInt(PREF_HTTP_PROXY_PORT));
+    socket.reset(new SocketCore());
     socket->establishConnection(resolvedAddresses.front(),
 				e->option->getAsInt(PREF_HTTP_PROXY_PORT));
     if(useProxyTunnel()) {
@@ -84,6 +85,7 @@ Command* HttpInitiateConnectionCommand::createNextCommand
     if(pooledSocket.isNull()) {
       logger->info(MSG_CONNECTING_TO_SERVER, cuid, req->getHost().c_str(),
 		   req->getPort());
+      socket.reset(new SocketCore());
       socket->establishConnection(resolvedAddresses.front(), req->getPort());
     } else {
       socket = pooledSocket;
diff --git a/src/InitiateConnectionCommandFactory.cc b/src/InitiateConnectionCommandFactory.cc
index 80503780..b38cd18f 100644
--- a/src/InitiateConnectionCommandFactory.cc
+++ b/src/InitiateConnectionCommandFactory.cc
@@ -42,6 +42,7 @@
 #include "StringFormat.h"
 #include "Option.h"
 #include "prefs.h"
+#include "SocketCore.h"
 
 namespace aria2 {
 
diff --git a/src/PeerAbstractCommand.cc b/src/PeerAbstractCommand.cc
index d8ee695f..05a2ba6a 100644
--- a/src/PeerAbstractCommand.cc
+++ b/src/PeerAbstractCommand.cc
@@ -52,18 +52,9 @@ PeerAbstractCommand::PeerAbstractCommand(int32_t cuid,
    checkSocketIsReadable(false), checkSocketIsWritable(false),
    uploadLimitCheck(false), uploadLimit(0), noCheck(false)
 {
-  setReadCheckSocket(socket);
-  timeout = e->option->getAsInt(PREF_BT_TIMEOUT);
-}
-
-PeerAbstractCommand::PeerAbstractCommand(int32_t cuid,
-					 const PeerHandle& peer,
-					 DownloadEngine* e)
-  :Command(cuid), e(e), socket(new SocketCore()), peer(peer),
-   checkSocketIsReadable(false), checkSocketIsWritable(false),
-   uploadLimitCheck(false), uploadLimit(0), noCheck(false)
-{
-  setReadCheckSocket(socket);
+  if(!socket.isNull() && socket->isOpen()) {
+    setReadCheckSocket(socket);
+  }
   timeout = e->option->getAsInt(PREF_BT_TIMEOUT);
 }
 
diff --git a/src/PeerAbstractCommand.h b/src/PeerAbstractCommand.h
index e44e1d58..95efdb99 100644
--- a/src/PeerAbstractCommand.h
+++ b/src/PeerAbstractCommand.h
@@ -80,11 +80,7 @@ public:
   PeerAbstractCommand(int32_t cuid,
 		      const SharedHandle<Peer>& peer,
 		      DownloadEngine* e,
-		      const SharedHandle<SocketCore>& s);
-
-  PeerAbstractCommand(int32_t cuid,
-		      const SharedHandle<Peer>& peer,
-		      DownloadEngine* e);
+		      const SharedHandle<SocketCore>& s = SharedHandle<SocketCore>());
 
   virtual ~PeerAbstractCommand();
 
diff --git a/src/PeerInitiateConnectionCommand.cc b/src/PeerInitiateConnectionCommand.cc
index 239dc946..ddaf53b3 100644
--- a/src/PeerInitiateConnectionCommand.cc
+++ b/src/PeerInitiateConnectionCommand.cc
@@ -75,6 +75,7 @@ PeerInitiateConnectionCommand::~PeerInitiateConnectionCommand()
 bool PeerInitiateConnectionCommand::executeInternal() {
   logger->info(MSG_CONNECTING_TO_SERVER, cuid, peer->ipaddr.c_str(),
 	       peer->port);
+  socket.reset(new SocketCore());
   socket->establishConnection(peer->ipaddr, peer->port);
   Command* command;
   if(_mseHandshakeEnabled) {
diff --git a/src/TrackerWatcherCommand.cc b/src/TrackerWatcherCommand.cc
index ba775274..302b3fdb 100644
--- a/src/TrackerWatcherCommand.cc
+++ b/src/TrackerWatcherCommand.cc
@@ -54,6 +54,7 @@
 #include "DlAbortEx.h"
 #include "Logger.h"
 #include "A2STR.h"
+#include "SocketCore.h"
 #include <sstream>
 
 namespace aria2 {