One domain multiple servers : <p>I have a domain <strong>mydomain.com</strong></p>

<p>I need to use this domain on multiple servers.
I have greengeeks shared hosting as well as AWS with few EC2 machines for my web applications.</p>

<p>mydomain.com is hosting a marketing site via greengeeks hosting and it also provides my email server. </p>

<p>I want one sub domain app.mydomain.com that will point to one of my ec2 instance, another subdomain appadmin.mydomain.com point to another ec2 instance, What is the best way to setup domains and sub-domains like this. (currently i am using different domain (mydomain.org) for my aws instance, which isn't elegant)</p>

<p>As my mail server is on greengeeks, and I programatically send email from my ec2 app server using an email id app@mydomain.com, some email clients shows warning as "cannot verify email origin" and some pushes it in spam folder, is there a solution to it, I read about MX and SPF record but I am confused how to create them and where to put them.</p>

<p>Thanks,
K</p>
