title: Sending emails using PHP's send() and the SPF issues
body: <p>I have a complicated question about sending emails..</p>
  
  <p>First I have a domain: mydomain.com
  I also have a "Domain mailbox", something like Google's Business mail service -- so I set the MX record to mxdomain.xxx.com</p>
  
  <p>I see that setting a txt record for SPF is good for my email sending therefore I added one like "v=spf1 include:spf.mail.xxx.com ~all" with "@".</p>
  
  <p>Then question comes..</p>
  
  <ol>
  <li><p>I found there are already two txt records: </p>
  
  <p><strong>@</strong>        v=spf1 a mx ptr include:secureserver.net ~all    1 Hour</p>
  
  <p><strong>admin</strong>    v=spf1 a mx ptr include:secureserver.net ~all    1 Hour</p></li>
  </ol>
  
  <p>Should I delete them and why..? </p>
  
  <ol start="2">
  <li><p>What are the difference between "@" and "admin"...??  </p></li>
  <li><p>On my website mydomain.com, I have a contact form, which will send automatical emails to me and to the one who fills the form. The form simply uses PHP's send() function, not using SMTP. 
  In my understanding, I should set two SPF record for my "domain-mailbox" and the web form, am I correct? Then how to do that? Or what you guys deal with it? </p></li>
  </ol>
  
  <hr>
  
  <p>These questions are actually very difficult since they relate to different things.. When I google them, people just give unclear solutions and they can't really explain their answers. If there are repeated answers on stackflow please tell me -- I really didn't find.. </p>
  
  <p>Thank you very much for your time.</p>