I have a "Google Apps for Domains" account for a customized domain name, call it mydomain.com. I also have a regular @gmail.com Google account where I do most of my emailing.
Long ago I setup a "Google Groups" address in the mydomain.com account, to forward all email to me at my @gmail.com account. For those unfamiliar with the terminology, a "Google Group" in this context is basically just an alias address.
Recently (April 2014 timeframe) I have noticed email sent to my mydomain.com account comes into my gmail.com account with a "From:" header that looks like this:
From: 'Real Sender' via myname <myname@mydomain.com>
Reply-to: Real Sender <realsender@address.com>
In other words, Gmail is making the email look like it's coming from me!
On my iPhone, this causes the actual name of the sender to show up with my own name, since iPhone Mail is pulling my name out of my address book, due to the use of my own email address in the "From:" header. Very confusing!
Is there any solution?
Best Answer
It turns out that Yahoo and AOL made changes in this timeframe to require mail providers that support the DMARC standard to reject all email from @yahoo.com accounts unless the mail actually originated at AOL and Yahoo's servers. (Other providers have followed suit.)
If you have a Google Group alias address forwarding to a gmail.com account, it will rewrite the From: header as explained in the scenario above if the sending provider has a strict DMARC policy like Yahoo and AOL's. If they didn't, the email may be rejected, depending on where it's being delivered. (Refer to the DMARC FAQ, where it appears Google has chosen option #3.)
The only way to resolve this (i.e. to prevent Google from rewriting the header), is to remove your Google Group alias address, and replace it with an actual Google Account you create with the same email address that you used to have for your Google Group alias. Then login to that new google account, and set it up to forward all incoming mail (or whatever email you really want) to your @gmail.com address.
Since I've made this change, I have not noticed Google rewriting any of the From: headers.