diff --git a/src/SocketCore.cc b/src/SocketCore.cc
index 12f569eb..a987d538 100644
--- a/src/SocketCore.cc
+++ b/src/SocketCore.cc
@@ -178,7 +178,7 @@ void SocketCore::bind(uint16_t port)
   struct addrinfo* rp;
   for(rp = res; rp; rp = rp->ai_next) {
     sock_t fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
-    if(fd == -1) {
+    if(fd == (sock_t) -1) {
       continue;
     }
     int sockopt = 1;
@@ -194,7 +194,7 @@ void SocketCore::bind(uint16_t port)
     break;
   }
   freeaddrinfo(res);
-  if(sockfd == -1) {
+  if(sockfd == (sock_t) -1) {
     throw DL_ABORT_EX(StringFormat(EX_SOCKET_BIND, "all addresses failed").str());
   }
 }
@@ -211,8 +211,8 @@ SocketCore* SocketCore::acceptConnection() const
   struct sockaddr_storage sockaddr;
   socklen_t len = sizeof(sockaddr);
   sock_t fd;
-  while((fd = accept(sockfd, reinterpret_cast<struct sockaddr*>(&sockaddr), &len)) == -1 && SOCKET_ERRNO == EINTR);
-  if(fd == -1) {
+  while((fd = accept(sockfd, reinterpret_cast<struct sockaddr*>(&sockaddr), &len)) == (sock_t) -1 && SOCKET_ERRNO == EINTR);
+  if(fd == (sock_t) -1) {
     throw DL_ABORT_EX(StringFormat(EX_SOCKET_ACCEPT, errorMsg()).str());
   }
   return new SocketCore(fd, _sockType);
@@ -260,7 +260,7 @@ void SocketCore::establishConnection(const std::string& host, uint16_t port)
   struct addrinfo* rp;
   for(rp = res; rp; rp = rp->ai_next) {
     sock_t fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
-    if(fd == -1) {
+    if(fd == (sock_t) -1) {
       continue;
     }
     int sockopt = 1;
@@ -274,7 +274,7 @@ void SocketCore::establishConnection(const std::string& host, uint16_t port)
     if(connect(fd, rp->ai_addr, rp->ai_addrlen) == -1 &&
        SOCKET_ERRNO != A2_EINPROGRESS) {
       CLOSE(sockfd);
-      sockfd = -1;
+      sockfd = (sock_t) -1;
       continue;
     }
     // TODO at this point, connection may not be established and it may fail
@@ -282,7 +282,7 @@ void SocketCore::establishConnection(const std::string& host, uint16_t port)
     break;
   }
   freeaddrinfo(res);
-  if(sockfd == -1) {
+  if(sockfd == (sock_t) -1) {
     throw DL_ABORT_EX(StringFormat(EX_SOCKET_CONNECT, host.c_str(),
 				 "all addresses failed").str());
   }
@@ -333,7 +333,7 @@ void SocketCore::closeConnection()
     gnutls_bye(sslSession, GNUTLS_SHUT_RDWR);
   }
 #endif // HAVE_LIBGNUTLS
-  if(sockfd != -1) {
+  if(sockfd != (sock_t) -1) {
     CLOSE(sockfd);
     sockfd = -1;
   }
diff --git a/src/SocketCore.h b/src/SocketCore.h
index aa46dc71..4cdaa473 100644
--- a/src/SocketCore.h
+++ b/src/SocketCore.h
@@ -141,7 +141,7 @@ public:
 
   sock_t getSockfd() const { return sockfd; }
 
-  bool isOpen() const { return sockfd != -1; }
+  bool isOpen() const { return sockfd != (sock_t) -1; }
 
   /**
    * Creates a socket and bind it with locahost's address and port.
@@ -161,7 +161,7 @@ public:
    * @param addrinfo placeholder to store host address and port.
    */
   void getAddrInfo(std::pair<std::string, uint16_t>& addrinfo) const;
-  
+
   /**
    * Stores peer's address and port to peerinfo.
    * @param peerinfo placeholder to store peer's address and port.
@@ -280,7 +280,7 @@ public:
   {
     return readDataFrom(reinterpret_cast<char*>(data), len, sender);
   }
-			
+
   /**
    * Reads up to len bytes from this socket, but bytes are not removed from
    * this socket.
@@ -291,7 +291,7 @@ public:
    * the number of bytes read to len.
    */
   void peekData(char* data, size_t& len);
-  
+
   void peekData(unsigned char* data, size_t& len)
   {
     peekData(reinterpret_cast<char*>(data), len);
@@ -311,11 +311,11 @@ public:
   bool operator==(const SocketCore& s) {
     return sockfd == s.sockfd;
   }
-  
+
   bool operator!=(const SocketCore& s) {
     return !(*this == s);
   }
-  
+
   bool operator<(const SocketCore& s) {
     return sockfd < s.sockfd;
   }