On 04/15/14 11:58, Andrew Sullivan wrote:
> On Tue, Apr 15, 2014 at 10:57:37AM -0400, Christopher Browne wrote:
>> Here is an announcement of a "block Yahoo users" policy just implemented by
>> another free software project (
>> http://lists.roaringpenguin.com/pipermail/remind-fans/2014/003025.html)
>> which seems to sum the issue up briefly but accurately.
>
> One alternative to this is to rewrite the From: address of Yahoo users
> when they enter the list, adding .invalid to the end of the mail
> address.  The resulting lookup for the DMARC record then looks in
> (say) yahoo.com.invalid.  You can't respond to such users, of course,
> and it may cause a lot of bounces, but fortunately .invalid is
> guaranteed not to work anywhere so at least the DNS lookups will be
> quick.

I am not in favor of shifting bounces around by deliberately creating 
invalid header content in order to make posting from Yahoo! addresses 
possible again. I am in favor of following exactly the same route and 
block all mail from @yahoo.com (and other DMARC participating ISPs) on 
our lists.

> I do encourage people who are using yahoo and who want to use mailing
> lists to ditch the yahoo account, however.  I also urge everyone to
> avoid yahoo as much as possible, because I think this behaviour was
> irresponsible and hostile to the Internet, and deserves to be shunned.

Ditto.

One aspect of the whole thing is that the DMARC proposal is two years 
old and it was well known that this (breaking mailing lists) would be a 
side effect of it. The powers that be at Yahoo! went ahead with it 
anyways. This can mean only one thing. That Yahoo! does not want users 
with a @yahoo.com address to participate in third party mailing lists. 
If that is what they want, then that is what they should get.


Regards,
Jan

-- 
Jan Wieck
Senior Software Engineer
http://slony.info