Q: double cname reference and resulting mx

[Doug Barton]

rgvt at gmx.net wrote:
> hello,
> 
> following scenario:
> 
> s3.dom.com -(cname)-> s2.dom.com -(cname)-> s1.dom.com
> 
> s2 & s3 do not have an associated mx.  only s1 has an mx.
> 
> what is the correct behaviour when sending mail to s3?
> 
> - the mx of s1 will be used and mail will be delivered
> - or mail will not come through

Either of those are possible. You should never chain CNAME's just on 
general principles, and if you want mail delivered to a host you're 
always better off making it an A record with its own MX.

It doesn't really matter who is "right" in this argument of yours. The 
fact is, if mail isn't getting delivered you need to do what it takes to 
make it work.

Doug