Index: openacs-4/packages/acs-mail-lite/tcl/acs-mail-lite-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-mail-lite/tcl/acs-mail-lite-procs.tcl,v
diff -u -N -r1.108.2.11 -r1.108.2.12
--- openacs-4/packages/acs-mail-lite/tcl/acs-mail-lite-procs.tcl	28 Oct 2020 15:39:19 -0000	1.108.2.11
+++ openacs-4/packages/acs-mail-lite/tcl/acs-mail-lite-procs.tcl	11 Nov 2020 16:59:57 -0000	1.108.2.12
@@ -805,6 +805,15 @@
             set fullMailMessage [mime::buildmessage $tokens]
 
             #
+            # 'dot-stuffing' as defined by RFC 5321 section 4.5.2:
+            #
+            # "Before sending a line of mail text, the SMTP client checks the
+            #  first character of the line.  If it is a period, one additional
+            #  period is inserted at the beginning of the line."
+            #
+            set fullMailMessage [string map {\n\. \n\.\.} $fullMailMessage]
+
+            #
             # Call "smtpd send" from the NaviServer nssmtpd module.
             # When the last two arguments are not provided, the
             # command uses host and port from the configuration