[Mailman-Users] Emails from yahoo members, are getting rejected by yahoo, "Service Unavailable".

Richard Damon Richard at Damon-Family.org
Sun Apr 13 22:01:39 CEST 2014

On 4/13/14, 3:48 PM, Mark London wrote:
> Hi - Starting this week, I've discovered that emails sent from yahoo
> members on my mailing lists, are not getting delivered to other yahoo
> addresses on my mailing list, including the person who sent the
> message.  My SMTP logs show that the message is getting rejected (see
> below).  I'm positive that the reason this is happening, is because I
> have my mailing list configured to preserve the original email
> address, in the From: line, while putting the mailing list address in
> the Reply-To:   If I specify that the mailing list address should also
> be in the From: address, the messages get delivered.
> I'm almost positive that Yahoo thinks that the message is spam, and
> rejecting it.  This is based on the fact that the same yahoo posts,
> when sent to Gmail members, are getting delivered to the Gmail user's
> Spam folder.  Gmail displays that the reason it's doing this, is that
> it can't verify that post is actually coming from yahoo.  This is a
> bit absurd, IMHO.  But at least the message is getting delivered!  In
> the case of yahoo, they simply reject the message!
> Apr 13 15:30:05 mail1 sendmail[6367]: s3DJU4jS006361:
> to=<XXXXXXXXXX at yahoo.com>, delay=00:00:00, xdelay=00:00:00,
> mailer=esmtp, pri=208395, relay=mta5.am0.yahoodns.net.
> [], dsn=5.0.0, stat=Service unavailable
> I would like to know if anyone else is seeing this behavior.  I've
> tried 2 different mailing list servers, and I see the same behavior. 
> Thanks. - Mark
You obviously haven't been reading much about mailinglists recently.
(Browse that last week of the archives)

Short version: Yahoo changed their DMARC settings to ask servers that
receive a message with a yahoo.com email address in the from line to
reject it if it isn't properly signed by yahoo, which all messages they
send will be.

If you list modifies the message, in particularly either the subject
line or body, then the signature won't match and the message is supposed
to not be delivered.

Basically, Yahoo has said that it users are not supposed to use any
mailinglist configured in the manner that they are often configured in.

Read the archives for a list of possible options.

Richard Damon

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