[Mailman-Users] no forwarding, how to debug?

[cls at pk.greens.org]

I've just installed 2.0.8.  I used the installation instructions
that come with the source, and Dave Sill's _Qmail Handbook_.
The Web admin interface works.  It sends welcome messages
to new subscribers.

If I select DELIVERY_MODULE = 'Sendmail' no messages are forwarded
at all.  I tried replacing /usr/lib/sendmail with a program that
simply logs its environment, arguments, and standard input
into a debug file.  It is never invoked at all.

If I select DELIVERY_MODULE = 'SMTPDirect' messages to 
subscribers on the local host are delivered.  Messages to
subscribers on other hosts are not.  /usr/lib/sendmail is
not being invoked.

In either case, messages sent to the list posting address appear
in the Web archive.  They are going into Mailman and not coming out.

The logs are not helpful.  Each failed delivery produces
a line in logs/bounce that says
<date> (<pid>) <listname>: <subscriber> - 3 more allowed over 431276 secs
but there is no hint of what was attempted or why it failed.
logs/error is empty.
My system allows relaying from localhost and its own routable address.
If a relay attempt fails, it's logged.  There is no relay attempt.

I would like to get more debug information.  Is there a switch somewhere
for that?
Is it mentioned anywhere in the documentation?

I would like to know what program Mailman is invoking, and what
arguments it passes.  Is that written down anywhere?
How can I find out what Mailman is doing?

When I get this working I will inform the relevant documentation
maintainers.

TIA


Cameron