[Xapian-discuss] Administrivia: Problems caused by Yahoo addresses

Olly Betts olly at survex.com
Fri Sep 11 23:55:43 BST 2015


A few hours ago 20 addresses got unsubscribed from this list due to
bounces caused by Yahoo's DMARC p=reject policy:

https://help.yahoo.com/kb/SLN24050.html

This breaks mailing lists.  Yahoo are well aware of this, but don't seem
to care:

http://www.pcworld.com/article/2141120/yahoo-email-antispoofing-policy-breaks-mailing-lists.html

The nearest Yahoo seem to come to useful advice is suggesting lists
should rewrite the "From:" header to be from the mailing list, which
breaks the way people expect mailing lists to work.

This change actually happened last year, but we've not hit issues so far
as we don't have many posts from Yahoo addresses.  Recently there have
been quite a few, so there's been a corresponding number of bounced
messages.

I've resubscribed the affected addresses - I'm fairly sure all were due
to this, but if anyone actually meant to unsubscribe, just remove
yourself again (and sorry for the inconvenience).

I've also disabled the footer that mailman was configured to add to
each message, as that breaks the DKIM signature on the message - my
understanding is that if that signature is good them the message
shouldn't bounce, so we'll see if that helps.  You can find links
for unsubscribing, etc in the message headers anyway.

Yahoo's DKIM signature also includes the "Subject:" header, so messages
which get the subject altered due to the addition of "[Xapian-discuss]"
probably also have a broken signature.  I'm not a fan of such tags
personally (and there are better headers to filter list email on), but I
know they are fairly popular so they're less of a no-brainer to just
turn off.

The other option is to ban posting to the list from Yahoo addresses (and
similarly for any other email providers who implement policies that
cause collateral damage such as this).  You could probably still
subscribe from such addresses, but it would be read-only.

Any thoughts?

Cheers,
    Olly



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