[57north-discuss] Anyone know how email works?

[Edward Watson]

On 5 June 2018 at 23:51, Robert McWilliam <rmcw at allmail.net> wrote:
> Would anyone like to learn stuff to try and figure this out? I really don't want to do that so please someone else volunteer :)

Hi Rob

I have an alias'ed gmail address via a google sites hosted domain and
I receive fine. I have had a quick google into the cause but all I
have so far come up with is maybe gmail's DMARC[1][2] policy. With
many of the popular providers using a 'DMARC = reject' policy to
prevent mail fraud, the 'FROM' address of a list email sent to
you at popularprovidorA.com from me at popularprovidorB.com via mailman is
seen to be lying since is actually came from the list.

If this is the case, I think the way round this is to use "FROM header
munging" in the mailman settings to rewrite the FROM header entry
'me at popularprovidorB.com' to
'me=popularprovidorB.com at lists.57north.co' which the receiving inbox
will not reject outright. The reply-to header can be left intact.

Changes to lists.57north.co's DNS records (over which DMARC works)
might also cause it to break like this [3] - have we changed this
recently?

About all this I could o/c be completely wrong o/c - this *is* the
result of a very quick search. I'll investigate further when I have
more time.

Cheers,
Nordin

[1] https://wiki.list.org/DEV/DMARC
[2] https://news.ycombinator.com/item?id=13425802
[3] http://mailman.9.n7.nabble.com/Recent-trouble-with-DMARC-Munging-td45873.html