CNAMES between two domains

Question

This is a two part question

PART 1

I have two domains

1. domain1.com, with a subdomain (sub1.sub2.domain1.com)
2. domain2.com, with no subdomains.

If I create a CNAME of corp.domain2.com, that points to sub1.sub2.domain1.com

Will that work? or do I need to configure anything from the domain1.com side of things?

PART 2

if sub1.sub2.domain1.com is secured with a wildcard SSL, and someone visits corp.domain2.com which is just a cname for sub1.sub2.domain1.com, will the browser invoke a SSL security warning?

Answer 1

Part 1: Yes. A CNAME is just one record, and it is only configured in one place. It doesn't even have to point to a valid name, but you will then get an error when you try to resolve it.

Part 2: If you open a browser to corp.domain2.com and the certificate says that the name is supposed to be *.domain1.com, then yes, you will get a warning.

You could configure a redirect on your web server to tell everyone coming to corp.domain2.com, that they should visit sub1.sub2.domain1.com instead. But this will only work if they open http://corp.domain2.com/. You will still see a warning if you open the SSL version at https://corp.domain2.com/ though.

Answer 2

Part 1

Yes, it will work.

In domain1.com dns, you need something like follow

    sub1.sub2    IN A     "some IP address"

or

    sub1.sub2    IN CNAME "some hostname"

Then in domain2.com, you add the CNAME

    corp         IN CNAME sub1.sub2.domain1.com.

Part 2

There should be no warning, as SSL is IP base. Following link actually answer in details

http://stackoverflow.com/questions/9935229/cname-ssl-certificates