[Mailman-Users] Dealing with ISPs that blacklist by message volune?

[Beau James]

Wondering whether anyone has suggestions for dealing with this situation.

I run two mailing lists for coachess (577 members) and referees
(377 members) in a local volunteer youth sports group.  Not exactly
large lists, and typically low traffic - 3 or 4 messages on a busy
day, none at all most days.  But occasionally, there will be a couple
of back-to-back messages e.g. a question and reply.

Because it is a local organization, the list members tend to have
email addresses concentrated in a few ISP domains e.g "sbcglobal.net",
"comcast.net" (plus a lot who use Yahoo or Gmail, of course).

Last week and again last night, the ISP server that hosts our domain
suddenly found itself on multiple blacklists.

The trigger seems to be that some of our subscriber's ISP domans don't
like "too many" incoming messages per hour from one originating domain.
Example:

  SomeMember at sbcglobal.net
    Domain ayso45.org has exceeded the max emails per hour. Message discarded.

Worse, some of these ISPs apparently report the domain and the IP address
of the originating MTA to some of the blacklist siets.  In very short order,
we're dead.  And so are all the other lists hosted on our ISPs server.

Rate-limiting messages from an originating domain seems like a brain-dead
anti-SPAM algorithm that makes discsussion lists unusable.  Our hosting
ISP tells me that we have to keep it under 60 *outbound* messages per hour
to stay under these recipient ISP's radar, and has suggested using "phplist"
to do so).  At 60 messages per hour, a single message to our small lists
would take 15 hours to be distributed (if the rate limiting is global and
not per recipient domain).

How are other's dealing with this?

Thanks,

Beau