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

Brian Carpenter brian at emwd.com
Mon Sep 8 20:56:30 CEST 2008

> -----Original Message-----
> From: mailman-users-bounces+brian=emwd.com at python.org [mailto:mailman-
> users-bounces+brian=emwd.com at python.org] On Behalf Of Beau James
> Sent: Monday, September 08, 2008 2:42 PM
> To: mailman-users at python.org
> Subject: [Mailman-Users] Dealing with ISPs that blacklist by message
> volune?
> 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

Hi Beau:

We do not rate limit our mailman clients and we rarely have any black list
problems. When it does happen, it is usually with a single ISP and the issue
is resolved within 24 hours. However this is very rare and all of our
mailman clients are very happy with our service.

We also make sure we have spf, domainkeys, and ptr records in place which
generally keeps the major ISPs happy. We also configure our mailman server
to send no more than 15 messages per smtp connection which seems to please
most isps.

We have one discussion list (medical software) that has over 3100 members
that ends up sending over a 100,000 messages in a typical 8 hour day and
this particular server has NEVER been blacklisted.

I don't agree with your hosting provider's recommendation at all. If you are
interested you can check our mailman service out at

Have a great day and I hope your list problems work out. Mailman is a
fantastic program. Don't let your hosting provider give it a bad rap.

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