diff --git a/CHANGES b/CHANGES
index 7530095..1eb202f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,12 @@
 Logbook Changelog
 =================
 
+Not yet released
+
+- Use correct record delimiters (null for UNIX, newline for network) in SyslogHandler (thanks Jonathan Kamens)
+- Try to reconnect to SyslogHandler TCP sockets when they are disconnected (thanks Jonathan Kamens)
+- Use RFC 5424 format for networking logging in SyslogHandler (thanks Jonathan Kamens)
+
 Here you can see the full list of changes between each Logbook release.
 
 Version 1.4.1
diff --git a/logbook/handlers.py b/logbook/handlers.py
index 3533445..72d7ebf 100644
--- a/logbook/handlers.py
+++ b/logbook/handlers.py
@@ -1535,7 +1535,7 @@ class SyslogHandler(Handler, StringFormatterHandlerMixin):
     def __init__(self, application_name=None, address=None,
                  facility='user', socktype=socket.SOCK_DGRAM,
                  level=NOTSET, format_string=None, filter=None,
-                 bubble=False):
+                 bubble=False, record_delimiter=None):
         Handler.__init__(self, level, filter, bubble)
         StringFormatterHandlerMixin.__init__(self, format_string)
         self.application_name = application_name
@@ -1546,14 +1546,24 @@ class SyslogHandler(Handler, StringFormatterHandlerMixin):
             else:
                 address = '/dev/log'
 
-        self.address = address
+        self.remote_address = self.address = address
         self.facility = facility
         self.socktype = socktype
 
         if isinstance(address, string_types):
             self._connect_unixsocket()
+            self.enveloper = self.unix_envelope
+            default_delimiter = u'\x00'
         else:
             self._connect_netsocket()
+            self.enveloper = self.net_envelope
+            default_delimiter = u'\n'
+
+        self.record_delimiter = default_delimiter \
+            if record_delimiter is None else record_delimiter
+
+        self.connection_exception = getattr(
+            __builtins__, 'BrokenPipeError', socket.error)
 
     def _connect_unixsocket(self):
         self.unixsocket = True
@@ -1569,7 +1579,7 @@ class SyslogHandler(Handler, StringFormatterHandlerMixin):
         self.unixsocket = False
         self.socket = socket.socket(socket.AF_INET, self.socktype)
         if self.socktype == socket.SOCK_STREAM:
-            self.socket.connect(self.address)
+            self.socket.connect(self.remote_address)
             self.address = self.socket.getsockname()
 
     def encode_priority(self, record):
@@ -1578,15 +1588,44 @@ class SyslogHandler(Handler, StringFormatterHandlerMixin):
                                                self.LOG_WARNING)
         return (facility << 3) | priority
 
-    def emit(self, record):
-        prefix = u('')
-        if self.application_name is not None:
-            prefix = self.application_name + u(':')
-        self.send_to_socket((u('<%d>%s%s\x00') % (
+    def wrap_segments(self, record, before):
+        msg = self.format(record)
+        segments = [segment for segment in msg.split(self.record_delimiter)]
+        return (before + segment + self.record_delimiter
+                for segment in segments)
+        
+    def unix_envelope(self, record):
+        before = u'<{}>{}'.format(
             self.encode_priority(record),
-            prefix,
-            self.format(record)
-        )).encode('utf-8'))
+            self.application_name + ':' if self.application_name else '')
+        return self.wrap_segments(record, before)
+
+    def net_envelope(self, record):
+        # Gross but effective
+        try:
+            format_string = self.format_string
+            application_name = self.application_name
+            if not application_name and record.channel and \
+               '{record.channel}: ' in format_string:
+                self.format_string = format_string.replace(
+                    '{record.channel}: ', '')
+                self.application_name = record.channel
+            # RFC 5424: <PRIVAL>version timestamp hostname app-name procid
+            #           msgid structured-data message
+            before = u'<{}>1 {}Z {} {} {} - - '.format(
+                self.encode_priority(record),
+                record.time.isoformat(),
+                socket.gethostname(),
+                self.application_name if self.application_name else '-',
+                record.process)
+            return self.wrap_segments(record, before)
+        finally:
+            self.format_string = format_string
+            self.application_name = application_name
+
+    def emit(self, record):
+        for segment in self.enveloper(record):
+            self.send_to_socket(segment.encode('utf-8'))
 
     def send_to_socket(self, data):
         if self.unixsocket:
@@ -1599,7 +1638,11 @@ class SyslogHandler(Handler, StringFormatterHandlerMixin):
             # the flags are no longer optional on Python 3
             self.socket.sendto(data, 0, self.address)
         else:
-            self.socket.sendall(data)
+            try:
+                self.socket.sendall(data)
+            except self.connection_exception:
+                self._connect_netsocket()
+                self.socket.send(data)
 
     def close(self):
         self.socket.close()

diff --git a/tests/test_logging_compat.py b/tests/test_logging_compat.py
index 31fdd40..7964993 100644
--- a/tests/test_logging_compat.py
+++ b/tests/test_logging_compat.py
@@ -33,7 +33,7 @@ def test_basic_compat(request, set_root_logger_level):
             with redirected_logging(set_root_logger_level):
                 logger.debug('This is from the old system')
                 logger.info('This is from the old system')
-                logger.warn('This is from the old %s', 'system')
+                logger.warning('This is from the old %s', 'system')
                 logger.error('This is from the old system')
                 logger.critical('This is from the old system')
                 logger.error('This is a %(what)s %(where)s', {'what': 'mapping', 'where': 'test'})
diff --git a/tests/test_mail_handler.py b/tests/test_mail_handler.py
index fd7730b..718d936 100644
--- a/tests/test_mail_handler.py
+++ b/tests/test_mail_handler.py
@@ -40,11 +40,11 @@ def test_mail_handler(activation_strategy, logger):
         header, data = mail.split('\n\n', 1)
         if 'Content-Transfer-Encoding: base64' in header:
             data = base64.b64decode(data).decode('utf-8')
-        assert re.search('Message type:\s+ERROR', data)
-        assert re.search('Location:.*%s' %
+        assert re.search(r'Message type:\s+ERROR', data)
+        assert re.search(r'Location:.*%s' %
                          re.escape(__file_without_pyc__), data)
-        assert re.search('Module:\s+%s' % __name__, data)
-        assert re.search('Function:\s+test_mail_handler', data)
+        assert re.search(r'Module:\s+%s' % __name__, data)
+        assert re.search(r'Function:\s+test_mail_handler', data)
         body = u('Viva la Espa\xf1a')
         if sys.version_info < (3, 0):
             body = body.encode('utf-8')
@@ -72,14 +72,14 @@ def test_mail_handler_batching(activation_strategy, logger):
     body, rest = pieces
     rest = rest.replace('\r', '')
 
-    assert re.search('Message type:\s+ERROR', body)
-    assert re.search('Module:\s+%s' % __name__, body)
-    assert re.search('Function:\s+test_mail_handler_batching', body)
+    assert re.search(r'Message type:\s+ERROR', body)
+    assert re.search(r'Module:\s+%s' % __name__, body)
+    assert re.search(r'Function:\s+test_mail_handler_batching', body)
 
     related = rest.strip().split('\n\n')
     assert len(related) == 2
-    assert re.search('Message type:\s+WARNING', related[0])
-    assert re.search('Message type:\s+DEBUG', related[1])
+    assert re.search(r'Message type:\s+WARNING', related[0])
+    assert re.search(r'Message type:\s+DEBUG', related[1])
 
     assert 'And this triggers it again' in mail_handler.mails[1][2]
 
@@ -101,14 +101,14 @@ def test_group_handler_mail_combo(activation_strategy, logger):
     body, rest = pieces
     rest = rest.replace('\r', '')
 
-    assert re.search('Message type:\\s+ERROR', body)
-    assert re.search('Module:\s+' + __name__, body)
-    assert re.search('Function:\s+test_group_handler_mail_combo', body)
+    assert re.search(r'Message type:\s+ERROR', body)
+    assert re.search(r'Module:\s+' + __name__, body)
+    assert re.search(r'Function:\s+test_group_handler_mail_combo', body)
 
     related = rest.strip().split('\n\n')
     assert len(related) == 2
-    assert re.search('Message type:\s+WARNING', related[0])
-    assert re.search('Message type:\s+DEBUG', related[1])
+    assert re.search(r'Message type:\s+WARNING', related[0])
+    assert re.search(r'Message type:\s+DEBUG', related[1])
 
 
 def test_mail_handler_arguments():
diff --git a/tests/test_syslog_handler.py b/tests/test_syslog_handler.py
index 9772a2a..d19d3f2 100644
--- a/tests/test_syslog_handler.py
+++ b/tests/test_syslog_handler.py
@@ -1,4 +1,5 @@
 import os
+import re
 import socket
 from contextlib import closing
 
@@ -7,33 +8,59 @@ from logbook.helpers import u
 
 import pytest
 
+unix_socket = "/tmp/__unixsock_logbook.test"
 
-def test_syslog_handler(logger, activation_strategy, unix_sock_path):
-    to_test = [
-        (socket.AF_INET, ('127.0.0.1', 0)),
-    ]
-    if hasattr(socket, 'AF_UNIX'):
-        to_test.append((socket.AF_UNIX, unix_sock_path))
-    for sock_family, address in to_test:
-        with closing(socket.socket(sock_family, socket.SOCK_DGRAM)) as inc:
-            inc.bind(address)
-            inc.settimeout(1)
-            for app_name in [None, 'Testing']:
-                handler = logbook.SyslogHandler(app_name, inc.getsockname())
-                with activation_strategy(handler):
-                    logger.warn('Syslog is weird')
-                try:
+to_test = [
+    (socket.AF_INET, socket.SOCK_DGRAM, ('127.0.0.1', 0)),
+    (socket.AF_INET, socket.SOCK_STREAM, ('127.0.0.1', 0)),
+]
+if hasattr(socket, 'AF_UNIX'):
+    to_test.append((socket.AF_UNIX, socket.SOCK_DGRAM, unix_socket))
+
+@pytest.mark.usefixtures("unix_sock_path")
+@pytest.mark.parametrize("sock_family,socktype,address", to_test)
+def test_syslog_handler(logger, activation_strategy,
+                        sock_family, socktype, address):
+    delimiter = {socket.AF_UNIX: '\x00',
+                 socket.AF_INET: '\n'}[sock_family]
+    with closing(socket.socket(sock_family, socktype)) as inc:
+        inc.bind(address)
+        if socktype == socket.SOCK_STREAM:
+            inc.listen(0)
+        inc.settimeout(1)
+        for app_name in [None, 'Testing']:
+            if sock_family == socket.AF_UNIX:
+                expected = (r'^<12>%stestlogger: Syslog is weird%s$' %
+                            (app_name + ':' if app_name else '',
+                             delimiter))
+            else:
+                expected = (r'^<12>1 \d{4}-\d\d-\d\dT\d\d:\d\d:\d\d(\.\d+)?Z %s %s %d '
+                            '- - %sSyslog is weird%s$' %
+                            (socket.gethostname(),
+                             app_name if app_name else 'testlogger',
+                             os.getpid(), 'testlogger: ' if app_name else '',
+                             delimiter))
+
+            handler = logbook.SyslogHandler(app_name, inc.getsockname(),
+                                            socktype=socktype)
+            with activation_strategy(handler):
+                logger.warn('Syslog is weird')
+            try:
+                if socktype == socket.SOCK_STREAM:
+                    with closing(inc.accept()[0]) as inc2:
+                        rv = inc2.recv(1024)
+                else:
                     rv = inc.recvfrom(1024)[0]
-                except socket.error:
-                    assert False, 'got timeout on socket'
-                assert rv == (
-                    u('<12>%stestlogger: Syslog is weird\x00') %
-                    ((app_name and (app_name + u(':'))) or u(''))).encode('utf-8')
+            except socket.error:
+                assert False, 'got timeout on socket'
+            rv = rv.decode('utf-8')
+            assert re.match(expected, rv), \
+                'expected {}, got {}'.format(expected, rv)
 
 
 @pytest.fixture
 def unix_sock_path(request):
-    returned = "/tmp/__unixsock_logbook.test"
+    returned = unix_socket
 
     @request.addfinalizer
     def cleanup():

Should use newline character, not null, for TCP record terminator
As per https://github.com/getlogbook/logbook/blob/master/logbook/handlers.py#L1430, Logbook marks the end of SyslogHandler records with a null character.

I don't know whether this is correct when sending to a socket, but as far as I can tell, the correct record terminator when sending over TCP is newline, not null, and no terminator should be included at all when sending over UDP.

Because it's using a null character instead of a newline, rsyslogd doesn't properly interpret messages sent to it by Logbook via TCP.

tests/test_syslog_handler.py::test_syslog_handler[ContextEnteringStrategy-AddressFamily.AF_INET-SocketKind.SOCK_DGRAM-address0] tests/test_syslog_handler.py::test_syslog_handler[ContextEnteringStrategy-AddressFamily.AF_INET-SocketKind.SOCK_STREAM-address1] tests/test_syslog_handler.py::test_syslog_handler[PushingStrategy-AddressFamily.AF_INET-SocketKind.SOCK_DGRAM-address0] tests/test_syslog_handler.py::test_syslog_handler[PushingStrategy-AddressFamily.AF_INET-SocketKind.SOCK_STREAM-address1]
tests/test_logging_compat.py::test_basic_compat[True] tests/test_logging_compat.py::test_basic_compat[False] tests/test_logging_compat.py::test_redirect_logbook tests/test_logging_compat.py::test_warning_redirections tests/test_mail_handler.py::test_mail_handler[ContextEnteringStrategy] tests/test_mail_handler.py::test_mail_handler[PushingStrategy] tests/test_mail_handler.py::test_mail_handler_batching[ContextEnteringStrategy] tests/test_mail_handler.py::test_mail_handler_batching[PushingStrategy] tests/test_mail_handler.py::test_group_handler_mail_combo[ContextEnteringStrategy] tests/test_mail_handler.py::test_group_handler_mail_combo[PushingStrategy] tests/test_mail_handler.py::test_mail_handler_arguments tests/test_syslog_handler.py::test_syslog_handler[ContextEnteringStrategy-AddressFamily.AF_UNIX-SocketKind.SOCK_DGRAM-/tmp/__unixsock_logbook.test] tests/test_syslog_handler.py::test_syslog_handler[PushingStrategy-AddressFamily.AF_UNIX-SocketKind.SOCK_DGRAM-/tmp/__unixsock_logbook.test]