2 files changed, 9 insertions, 0 deletions
diff --git a/NEWS b/NEWS
index 0e470bf4..38ad8571 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,9 @@ Here is a history of user visible changes to Mailman.
 
   Bug Fixes and other patches
 
+    - Fixed bin/genaliases to not throw TypeError when MTA = None.
+      Bug #587657.
+
     - Provided the ability to specify in mm_cfg.py a local domain (e.g.
       'localhost') for the local addresses in the generated virtual-mailman
       when MTA = 'Postfix'.  See VIRTUAL_MAILMAN_LOCAL_DOMAIN in Defaults.py.
diff --git a/bin/genaliases b/bin/genaliases
index 18b67efe..0a1a3dae 100644
--- a/bin/genaliases
+++ b/bin/genaliases
@@ -79,6 +79,12 @@ def main():
     if args:
         usage(1)
 
+    if not mm_cfg.MTA:
+        mta = repr(mm_cfg.MTA)
+        usage(2, _(
+            "genaliases can't do anything useful with mm_cfg.MTA = %(mta)s."
+             ))
+
     # Import the MTA specific module
     modulename = 'Mailman.MTA.' + mm_cfg.MTA
     __import__(modulename)