diff --git a/Net/include/Poco/Net/MailStream.h b/Net/include/Poco/Net/MailStream.h
index e6500cd7c..869101b6d 100644
--- a/Net/include/Poco/Net/MailStream.h
+++ b/Net/include/Poco/Net/MailStream.h
@@ -65,6 +65,7 @@ private:
 	{
 		ST_DATA,
 		ST_CR,
+		ST_LF,
 		ST_CR_LF,
 		ST_CR_LF_DOT,
 		ST_CR_LF_DOT_DOT,
diff --git a/Net/src/MailStream.cpp b/Net/src/MailStream.cpp
index 278e591c7..6fff64650 100644
--- a/Net/src/MailStream.cpp
+++ b/Net/src/MailStream.cpp
@@ -132,7 +132,7 @@ int MailStreamBuf::writeToDevice(char c)
 		if (_state == ST_CR)
 			_state = ST_CR_LF;
 		else
-			_state = ST_DATA;
+			_state = ST_LF;
 		break;
 	case '.':
 		if (_state == ST_CR_LF)
@@ -152,6 +152,11 @@ int MailStreamBuf::writeToDevice(char c)
 		}
 		_pOstr->put(c);
 	}
+	else if (_state == ST_LF)
+	{
+		_buffer += "\r\n";
+		_state = ST_CR_LF;
+	}
 	else if (_state == ST_CR_LF_DOT)
 	{
 		// buffer contains one or more CR-LF pairs
diff --git a/Net/testsuite/src/MailStreamTest.cpp b/Net/testsuite/src/MailStreamTest.cpp
index 7b23abe46..fc668b901 100644
--- a/Net/testsuite/src/MailStreamTest.cpp
+++ b/Net/testsuite/src/MailStreamTest.cpp
@@ -72,6 +72,7 @@ void MailStreamTest::testMailOutputStream()
 		"Subject: test\r\n"
 		"\r\n"
 		"This is a test.\r\n"
+		"\n.\n"
 		"\rThis.is.\ngarbage\r.\r\n"
 		".This line starts with a period.\r\n"
 		"\r\n"
@@ -90,7 +91,8 @@ void MailStreamTest::testMailOutputStream()
 		"Subject: test\r\n"
 		"\r\n"
 		"This is a test.\r\n"
-		"\rThis.is.\ngarbage\r.\r\n"
+		"\r\n..\r\n"
+		"\rThis.is.\r\ngarbage\r.\r\n"
 		"..This line starts with a period.\r\n"
 		"\r\n"
 		"..and this one too\r\n"