diff --git a/src/calibre/utils/smtp.py b/src/calibre/utils/smtp.py
index 5455b9896c..4bbd421075 100644
--- a/src/calibre/utils/smtp.py
+++ b/src/calibre/utils/smtp.py
@@ -12,6 +12,7 @@ This module implements a simple commandline SMTP client that supports:
 
 import sys, traceback, os, socket, encodings.idna as idna
 from calibre import isbytestring, force_unicode
+from calibre.constants import ispy3
 
 
 def safe_localhost():
@@ -24,7 +25,7 @@ def safe_localhost():
         # https://bugs.launchpad.net/bugs/1256549
         try:
             local_hostname = idna.ToASCII(force_unicode(fqdn))
-        except:
+        except Exception:
             local_hostname = 'localhost.localdomain'
     else:
         # We can't find an fqdn hostname, so use a domain literal
@@ -104,7 +105,7 @@ def get_mx(host, verbose=0):
 
 def sendmail_direct(from_, to, msg, timeout, localhost, verbose,
         debug_output=None):
-    import calibre.utils.smtplib as smtplib
+    import polyglot.smtplib as smtplib
     hosts = get_mx(to.split('@')[-1].strip(), verbose)
     timeout=None  # Non blocking sockets sometimes don't work
     kwargs = dict(timeout=timeout, local_hostname=localhost or safe_localhost())
@@ -133,7 +134,7 @@ def sendmail(msg, from_, to, localhost=None, verbose=0, timeout=None,
     if relay is None:
         for x in to:
             return sendmail_direct(from_, x, msg, timeout, localhost, verbose)
-    import calibre.utils.smtplib as smtplib
+    import polyglot.smtplib as smtplib
     cls = smtplib.SMTP_SSL if encryption == 'SSL' else smtplib.SMTP
     timeout = None  # Non-blocking sockets sometimes don't work
     port = int(port)
@@ -153,7 +154,7 @@ def sendmail(msg, from_, to, localhost=None, verbose=0, timeout=None,
         s.starttls(context=context)
         s.ehlo()
     if username is not None and password is not None:
-        if encryption == 'SSL':
+        if encryption == 'SSL' and not ispy3:
             s.sock = s.file.sslobj
         s.login(username, password)
     ret = None
diff --git a/src/calibre/utils/smtplib.py b/src/calibre/utils/smtplib.py
index b15bc6988c..42ff37d3b0 100755
--- a/src/calibre/utils/smtplib.py
+++ b/src/calibre/utils/smtplib.py
@@ -48,7 +48,7 @@ import re
 import email.utils
 import base64
 import hmac
-from email.base64mime import encode as encode_base64
+from email.base64mime import body_encode as encode_base64
 from sys import stderr
 from functools import partial
 
@@ -282,7 +282,7 @@ class SMTP:
             # if that can't be calculated, that we should use a domain literal
             # instead (essentially an encoded IP address like [A.B.C.D]).
             fqdn = socket.getfqdn()
-            if '.' in fqdn and fqdn != '.':  # Changed by Kovid
+            if '.' in fqdn:
                 self.local_hostname = fqdn
             else:
                 # We can't find an fqdn hostname, so use a domain literal
@@ -345,11 +345,6 @@ class SMTP:
         """Send `str' to the server."""
         if self.debuglevel > 0:
             raw = repr(str)
-            if self.debuglevel < 2:
-                if len(raw) > 100:
-                    raw = raw[:100] + '...'
-                if 'AUTH' in raw:
-                    raw = 'AUTH <censored>'
             self.debug('send:', raw)
         if hasattr(self, 'sock') and self.sock:
             try:
diff --git a/src/polyglot/smtplib.py b/src/polyglot/smtplib.py
new file mode 100644
index 0000000000..0ee340a85f
--- /dev/null
+++ b/src/polyglot/smtplib.py
@@ -0,0 +1,73 @@
+#!/usr/bin/env python2
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import sys
+from functools import partial
+
+from polyglot.builtins import is_py3
+
+
+class FilteredLog(object):
+
+    ' Hide AUTH credentials from the log '
+
+    def __init__(self, debug_to=None):
+        self.debug_to = debug_to or partial(print, file=sys.stderr)
+
+    def __call__(self, *a):
+        if a and len(a) == 2 and a[0] == 'send:':
+            a = list(a)
+            raw = a[1]
+            if len(raw) > 100:
+                raw = raw[:100] + (b'...' if isinstance(raw, bytes) else '...')
+            q = b'AUTH ' if isinstance(raw, bytes) else 'AUTH '
+            if q in raw:
+                raw = 'AUTH <censored>'
+            a[1] = raw
+        self.debug_to(*a)
+
+
+if is_py3:
+    import smtplib
+
+    class SMTP(smtplib.SMTP):
+
+        def __init__(self, *a, **kw):
+            self.debug_to = FilteredLog(kw.pop('debug_to', None))
+            super().__init__(*a, **kw)
+
+        def _print_debug(self, *a):
+            if self.debug_to is not None:
+                self.debug_to(*a)
+            else:
+                super()._print_debug(*a)
+
+    class SMTP_SSL(smtplib.SMTP_SSL):
+
+        def __init__(self, *a, **kw):
+            self.debug_to = FilteredLog(kw.pop('debug_to', None))
+            super().__init__(*a, **kw)
+
+        def _print_debug(self, *a):
+            if self.debug_to is not None:
+                self.debug_to(*a)
+            else:
+                super()._print_debug(*a)
+
+else:
+    import calibre.utils.smtplib as smtplib
+
+    class SMTP(smtplib.SMTP):
+
+        def __init__(self, *a, **kw):
+            kw['debug_to'] = FilteredLog(kw.get('debug_to'))
+            smtplib.SMTP.__init__(self, *a, **kw)
+
+    class SMTP_SSL(smtplib.SMTP_SSL):
+
+        def __init__(self, *a, **kw):
+            kw['debug_to'] = FilteredLog(kw.get('debug_to'))
+            smtplib.SMTP_SSL.__init__(self, *a, **kw)