[Mailman-Users] Problems with undeliverable mail

[Charlie Watts]

On Sat, 29 Dec 2001, Michelle Brownsworth wrote:
> >On Thu, 27 Dec 2001 14:06:53 -0800
> >Michelle Brownsworth <michelle at primelogic.com> wrote:
> >
> >>  My mailhost is chugging away, trying over and over to deliver to a
> >>  large batch of addresses with a .gov domain that doesn't resolve;
> >>  this particular .gov nameserver is obviously having problems.  And
> >>  it's not from the sendmail's mail queue; /var/spool/mqueue/ is
> >>  completely empty.  It's Mailman reattempting to send to the
> >>  problem addresses.
> >
> >Configure your MTA to not do DNS verifies on deliveries from
> >localhost.
>
> But since none of the subscribers are local, I don't see how that
> will help in this situation.  And as I said, the batch of reattempts
> didn't seem to be coming from sendmail's mail queue.  The only
> explanation is that Mailman must have a means of keeping track of
> failed deliveries.

Perhaps a re-phrasing: configure your MTA to blindly accept mail from
localhost without verifying that the *destination* domain is valid.

Many MTA configurations won't accept mail that they know they can't
deliver - if the destination domain doesn't resolve, there's no point in
accepting it. So the MTA reports, typically, a temporary SMTP error.

Sounds like Mailman is trying, over and over, to get these messages into
the MTA.

If you instead configure your MTA to accept the message, it will accept it
and immediately generate a bounce. Mailman does the right thing with
bounces.

Here's an example: my list of SMTPD restrictions from postfix. I reject
mail for unknown recipient domains - but I have an exception list for my
list servers. /etc/postfix/class_host_exception includes localhost and a
few other machines that I let dump blindly into the system.

smtpd_recipient_restrictions =
        check_client_access hash:/etc/postfix/class_host_exception,
        reject_unknown_sender_domain,
        reject_unknown_recipient_domain,
        reject_unauth_pipelining,
        permit_mynetworks,
        reject_unauth_destination,
        reject_non_fqdn_sender,
        reject_non_fqdn_recipient,
        reject_invalid_hostname,
        permit

This can also speed up injection into the MTA, if that's important to you.

-- 
Charlie Watts
cewatts at frontier.net
Frontier Internet
http://www.frontier.net/