dig returns different IP address when dropping the “www.” from domain name

Question

I have performed a dig on my domain name used on my site and I seem to be getting different results when I drop the "www." from the lookup. I am concerned this is causing me issues within my application, however i'm not sure if it's a red herring or not.

When I do this:

 dig @8.8.8.8 www.php53.staging-crm.com

I get:

;; ANSWER SECTION:
www.php53.staging-crm.com. 14400 IN A    165.160.xx.xx
www.php53.staging-crm.com. 14400 IN A    165.160.xx.xx

Similarly, when I drop the "www.":

 dig @8.8.8.8 php53.staging-crm.com

I get:

;; ANSWER SECTION:
php53.staging-crm.com. 14400 IN  A       80.75.xx.xx

(full IP addresses have been removed).

What would cause these to return different IP addresses?

Answer 1

Whatever dig reports is the truth. You should conclude that www.php53.staging-crm.com maps to 165.160.x.x and php53.staging-crm.com maps to 80.75.x.x.

There is no particular reason why they should map to the same address. It is common these days to have the unadorned domain name map to the same address as www for the convenience of web users, but that is nothing more than a convention. Your domain's entries just aren't defined that way now.

Answer 2

Actually the domain name www.php53.staging-crm.com is the child domain of php53.staging-crm.com. They may or may not map to the same address. In your case both are mapped to two different IP addresses.