[Mailman-Users] list messages lost to Hotmail subscribers lost

[Jeff Donsbach]

Hi,
   I recently started having delivery problems with list messages to
Hotmail subscribers. The problem seems to have started on or around
June 10. I checked the syslog file and was seeing occasional (452 too
many recipients for delivery) errors. I changed SMTP_MAX_RCPTS to 5
and SMTP_MAX_SESSIONS_PER_CONNECTION to 5 as well. That seems to have
cleared up the '452' errors. All messages handed off to Hotmail users
in the last 24 hours or so have (250  <messageid at domain.tld> Queued
mail for delivery)  successful return codes (as far as I see). Yet,
none of the list subscribers are receiving messages. If I send a test
message to some of the subscribers directly (not via Mailman), they
get it.

Beyond telling people to dump Hotmail, does anyone have any "best
practices" they can share for getting Mailman messages delivered to
Hotmail subscribers successfully? I have already read FAQ 3.42 on the
new FAQ wiki (thanks, Barry and Co). And, I have already read -
http://postmaster.live.com/Guidelines.aspx , and my co-admin and I are
looking into implementing SenderId/SPF keys for the domain DNS
records.

Any other advice for Hotmail?
Thanks in advance