Index: src/OFDDPSocket.m
==================================================================
--- src/OFDDPSocket.m
+++ src/OFDDPSocket.m
@@ -194,12 +194,14 @@
 	struct iovec iov[2] = {
 		{ &protocolType, 1 },
 		{ buffer, length }
 	};
 	struct msghdr msg = {
-		.msg_name = (struct sockaddr *)&sender->sockaddr,
-		.msg_namelen = (socklen_t)sizeof(sender->sockaddr),
+		.msg_name = (sender != NULL
+		    ? (struct sockaddr *)&sender->sockaddr : NULL),
+		.msg_namelen = (sender != NULL
+		    ? (socklen_t)sizeof(sender->sockaddr) : 0),
 		.msg_iov = iov,
 		.msg_iovlen = 2
 	};
 
 	if (_socket == OFInvalidSocketHandle)
@@ -214,12 +216,14 @@
 	if (ret < 1 || protocolType != _protocolType)
 		@throw [OFReadFailedException exceptionWithObject: self
 						  requestedLength: length
 							    errNo: ENOMSG];
 
-	sender->length = msg.msg_namelen;
-	sender->family = OFSocketAddressFamilyAppleTalk;
+	if (sender != NULL) {
+		sender->length = msg.msg_namelen;
+		sender->family = OFSocketAddressFamilyAppleTalk;
+	}
 
 	return ret - 1;
 }
 
 - (void)sendBuffer: (const void *)buffer

Index: src/OFDNSResolver.m
==================================================================
--- src/OFDNSResolver.m
+++ src/OFDNSResolver.m
@@ -908,11 +908,12 @@
 		return true;
 
 	if (context->_TCPSocket != nil) {
 		if ([_TCPQueries objectForKey: context->_TCPSocket] != context)
 			return true;
-	} else if (!OFSocketAddressEqual(sender, &context->_usedNameServer))
+	} else if (sender == NULL ||
+	    !OFSocketAddressEqual(sender, &context->_usedNameServer))
 		return true;
 
 	[context->_cancelTimer invalidate];
 	[context->_cancelTimer release];
 	context->_cancelTimer = nil;

Index: src/OFDatagramSocket.h
==================================================================
--- src/OFDatagramSocket.h
+++ src/OFDatagramSocket.h
@@ -158,11 +158,11 @@
  * @throw OFReadFailedException Receiving failed
  * @throw OFNotOpenException The socket is not open
  */
 - (size_t)receiveIntoBuffer: (void *)buffer
 		     length: (size_t)length
-		     sender: (OFSocketAddress *)sender;
+		     sender: (nullable OFSocketAddress *)sender;
 
 /**
  * @brief Asynchronously receives a datagram and stores it into the specified
  *	  buffer.
  *

Index: src/OFDatagramSocket.m
==================================================================
--- src/OFDatagramSocket.m
+++ src/OFDatagramSocket.m
@@ -171,58 +171,63 @@
 	ssize_t ret;
 
 	if (_socket == OFInvalidSocketHandle)
 		@throw [OFNotOpenException exceptionWithObject: self];
 
-	sender->length = (socklen_t)sizeof(sender->sockaddr);
+	if (sender != NULL)
+		sender->length = (socklen_t)sizeof(sender->sockaddr);
 
 #ifndef OF_WINDOWS
 	if ((ret = recvfrom(_socket, buffer, length, 0,
-	    (struct sockaddr *)&sender->sockaddr, &sender->length)) < 0)
+	    (sender != NULL ? (struct sockaddr *)&sender->sockaddr : NULL),
+	    (sender != NULL ? &sender->length : NULL))) < 0)
 		@throw [OFReadFailedException
 		    exceptionWithObject: self
 			requestedLength: length
 				  errNo: OFSocketErrNo()];
 #else
 	if (length > INT_MAX)
 		@throw [OFOutOfRangeException exception];
 
 	if ((ret = recvfrom(_socket, buffer, (int)length, 0,
-	    (struct sockaddr *)&sender->sockaddr, &sender->length)) < 0)
+	    (sender != NULL ? (struct sockaddr *)&sender->sockaddr : NULL),
+	    (sender != NULL ? &sender->length : NULL))) < 0)
 		@throw [OFReadFailedException
 		    exceptionWithObject: self
 			requestedLength: length
 				  errNo: OFSocketErrNo()];
 #endif
 
-	switch (((struct sockaddr *)&sender->sockaddr)->sa_family) {
-	case AF_INET:
-		sender->family = OFSocketAddressFamilyIPv4;
-		break;
+	if (sender != NULL) {
+		switch (((struct sockaddr *)&sender->sockaddr)->sa_family) {
+		case AF_INET:
+			sender->family = OFSocketAddressFamilyIPv4;
+			break;
 #ifdef OF_HAVE_IPV6
-	case AF_INET6:
-		sender->family = OFSocketAddressFamilyIPv6;
-		break;
+		case AF_INET6:
+			sender->family = OFSocketAddressFamilyIPv6;
+			break;
 #endif
 #ifdef OF_HAVE_UNIX_SOCKETS
-	case AF_UNIX:
-		sender->family = OFSocketAddressFamilyUNIX;
-		break;
+		case AF_UNIX:
+			sender->family = OFSocketAddressFamilyUNIX;
+			break;
 #endif
 #ifdef OF_HAVE_IPX
-	case AF_IPX:
-		sender->family = OFSocketAddressFamilyIPX;
-		break;
+		case AF_IPX:
+			sender->family = OFSocketAddressFamilyIPX;
+			break;
 #endif
 #ifdef OF_HAVE_APPLETALK
-	case AF_APPLETALK:
-		sender->family = OFSocketAddressFamilyAppleTalk;
-		break;
+		case AF_APPLETALK:
+			sender->family = OFSocketAddressFamilyAppleTalk;
+			break;
 #endif
-	default:
-		sender->family = OFSocketAddressFamilyUnknown;
-		break;
+		default:
+			sender->family = OFSocketAddressFamilyUnknown;
+			break;
+		}
 	}
 
 	return ret;
 }