Fall back to HELO when EHLO (an optional extension) fails

doc/CHANGES.rst

@@ -5,6 +5,14 @@ This file contains change information for the current Zope release.
 Change information for previous versions of Zope can be found in the
 file HISTORY.txt.
 
+Zope 2.12.4 (Unreleased)
+------------------------
+
+Bugs Fixed
+++++++++++
+
+- MailHost should fall back to HELO when EHLO fails.
+
 Zope 2.12.3 (2010/01/12)
 ------------------------
 

src/Products/MailHost/mailer.py

@@ -49,8 +49,10 @@ class SMTPMailer(object):
         # send EHLO
         code, response = connection.ehlo()
         if code < 200 or code >300:
-            raise RuntimeError('Error sending EHLO to the SMTP server '
-                                '(code=%s, response=%s)' % (code, response))
+            code, response = connection.helo()
+            if code < 200 or code >300:
+                raise RuntimeError('Error sending HELO to the SMTP server '
+                                   '(code=%s, response=%s)' % (code, response))
 
         # encryption support
         have_tls =  connection.has_extn('starttls')