David,
Try sending email via telnet to yahoo, I think that you will find that this
in fact isn't just an issue for list mail but for all mail sent to the
domain. 

Paul Russell has suggested that the LSTSRV-L is the appropriate list for the
yahoo issues, see below your message.  

~Chris


-----Original Message-----
From: LISTSERV site administrators' forum
[mailto:[log in to unmask]] On Behalf Of David Rosenthal
Sent: Wednesday, October 25, 2006 6:42 AM
To: [log in to unmask]
Subject: Yahoo.com

Starting at 1 am 10/23/06, yahoo.com began deferring all of the mail from
our server (shamash.org[12.107.129.86])) with  "Deferred: 421 Too many
recipients"

We reported this on 10/23/06 via phone and were told to email
[log in to unmask], which we did.  We still have not heard back from
yahoo.com's postmaster.  When we called, we were told that we could not
speak to anyone in the NOC/Abuse/Postmaster staff unless we had the name of
a "non-executive employee that worked in that department".

A few questions for fellow ListServ site managers:
1) We have always sent out 50 messages per SMTP transaction.  How many do
you send out per message?
2) It seems as though yahoo put into place a new multiple-recipient policy.
Do they publish these policy changes anywhere?  (is there an email list we
can join)  Does any other site know what yahoo's current limit on RCPT in a
single message?
3) Can someone mail me (not the list) the name (and/or email address) of
some human in yahoo's Abuse/NOC/Postmaster department so I can reach
someone?
4) Have you implemented Domain-Keys for ListServ? If so do you sign all of
the mail which goes through ListServ, or only mail which originates from the
server (administrative mail, digests, indexes)

-- 
   David Rosenthal, D.O.
   Shamash Coordinator http://shamash.org

On 10/24/2006 10:52, Pete Weiss wrote:
> At 10:00 10/24/2006 Tuesday, Chris Mead wrote:
>> This probably isn't the correct forum to discuss this but from what I 
>> can tell Yahoo has recently made changes that are causing all sorts 
>> of problems for a lot of people.  The following error is received 
>> when attempting to connect to the yahoo.com mail servers.
>>  
>> 451 Message temporarily deferred - 4.16.50
>>
>> We have been waiting for a postmaster response to the issue since last
week.
> 
> I believe LSTSRV-L is * a * correct list to post to, since many LISTSERV
admins will be able to either provide insight or may be suffering the same
pain and would appreciate "the company" i.e., knowing what others are
experiencing and not go down wrong problem source ID paths.
> 
> On some lists, commercial ISP postmasters even hang out and are 
> willing to dialogue, right Paul.R ? :-)
> 

Postmaster staff from both AOL and Yahoo are subscribed to the
HiEd-EmailAdmin list, at the invitation of the list owners, and have
responded to questions and problem reports from list subscribers.

The HiEd-EmailAdmin list exists to facilitate discussion about all aspects
of email administration and management in higher education environments. The
list archives are accessible to the public, however, you must subscribe to
the list in order to post to the list. The primary audience is email
administrators in higher education, however, all members of the higher
education community are welcome to join the list. As a general rule, vendors
and their representatives will not be allowed to join the list.

HiEd-EmailAdmin list archives:
http://listserv.nd.edu/archives/hied-emailadmin.html

--
Paul Russell, Senior Systems Administrator OIT Messaging Services Team
University of Notre Dame [log in to unmask]