Google Apps on a subdomain with CNAME, how to setup MX records?

Question

I've mapped a Google App Engine application using "Google Apps for your domain" on one subdomain (say "app.mydomain.com" ) and I've done that with a CNAME record in the DNS settings for mydomain.com.

Is it possible for Google Apps to handle e-mails sent to "@app.mydomain.com"? In the DNS record for mydomain.com, I would have a configuration like this:

app.mydomain.com. CNAME   GHS.GOOGLE.COM.
app.mydomain.com. MX    1 ASPMX.L.GOOGLE.COM.

Would the CNAME entry for the subdomain conflict with MX records for the same subdomain?

[edit] The root domain MX record @mydomain.com is NOT setup with Google Apps

[edit2] [related question on Stack Exchange]1

Answer 1

As correctly answered on the related Stack Overflow post you've linked to, It's not possible.

A CNAME resource record cannot coexist with another one for the same zone. You can refer to RFC1034 and RFC2181 for the following:

If a CNAME RR is present at a node, no other data should be present;

There may be only one such canonical name for any one alias.

Answer 2

It is exactly the same to set up MX records for sub domains.

So for mydomain.com and app.mydomain.com would like this in Bind

@ IN MX aspmx.l.google.com app IN MX aspmx.l.google.com.

In case you need to validate the domain

app IN TXT "some long code goes here."

Answer 3

You should be able to setup an alias domain as documented at http://support.google.com/a/bin/answer.py?hl=en&answer=53295.

HOWEVER: you won't be able to maintain separate users for your subdomain. That will probably be an issue. I'd recommend looking at one of the folks who do mail to URL routing (like mailgun or Sendgrid): you could have mail POSTed to your app engine app, and then extract the recipient info and deal with it appropriately.

EDIT: ah, misunderstood. Now, correct me if I'm wrong, but you're trying to have Google Apps handle all emails for a subdomain of an existing domain that is not already a Google Apps domain? If that's the case then you probably can't do this, since DNS basically won't let you assign different MX records to a CNAME'd subdomain. You can either use A records or point your root MX records at Google Apps (and then subdomain mail will go to the same place).

Answer 4

under your DNS MX records, you can define the host name. e.g. "reseller" that will setup MX records for email domain "reseller.yourdomain.com"

That is the field that google app setup will ask to put as "@" or