How should I set up my PTR Record?

Question

I am using wamp server on Windows with the sendmail program. I am trying to send an e-mail from my personal computer with my business email.

I configured the sendmail.ini

smtp_server=localhost
smtp_port=1055
default_domain=company.something
[email protected]
auth_password= *****

I also changed the php.ini

SMTP = localhost
smtp_port = 1055
sendmail_path = "path\to\sendmail.exe"

And after reading others questions I used this trick

1º Right click on sendmail.exe    
2º Properties    
3º Compatibility    
4º Change the configuration for all users    
5º Execute as Windows XP SP 3    
6º Execute as adminitrator

But still got the "Connection Closed Gracefully." error. I am sure that my SMTP is correct because I use the same with Thunderbird and it run everyday since a year ago without any problem.

I am also sure that my configuration is well working because I tried to change the parameters to use a gmail account and it is working.

I just want to know, what this error mean ?

Solution

It does not matter what domain you're sending e-mail for. Explicitly, it does not matter what your employee's e-mail addresses are, it does not matter if they're [email protected]. I need to make that point 100% clear because everyone assumes it has something to do with this.

Now, your e-mail server has a hostname. For many companies it something like mail.example.com. This is what matters in regards to the PTR record. DNS for the mail server must match forward, backward, and with regards to the SMTP communications.

That means:

1. Your forward host name must resolve to the correct IP.
   mail.example.com must resolve to 1.1.1.1
2. Your reverse pointer must resolve to the correct host name.
   1.1.1.1 must point to mail.example.com
3. When your server connects to another server, it must connect from IP 1.1.1.1 and announce itself as mail.example.com (the HELO or EHLO message).

If you have more than one server they each get their own host name (eg mail1.example.com and mail2.example.com), and the above has to be true for each server.

Comments

[bhamby]

I'm not sure what you're looking to achieve with the PTR record then. Usually with PTR's it's to create a reverse DNS lookup (IP -> domain) so that email clients can be sure that that is the correct IP for that domain. You (probably) do this at the host, because they own your IP. If this is about SPF, then you just need to create the TXT record for the domain you want to authenticate (e.g., a TXT on example.com), no PTR necessary.

[Jake]

Is there a diagram for this? This thing is really confusing everywhere I read.

[Jake]

@Henry Wrinkle Were you are to set this up? what galador might be saying is that the PTR is not set at the DNS zone for example.com, but rather at your ISP's zone.

[Jake]

Do I need to do anything i.e. set PTR records at my own zone in exmaple.com? Or the ISP providing the dedicated IP will handle it?

[Philip]

PTR records are only set on the reverse lookup (ie IN-ADDR.ARPA). The "A" and "MX" records are only for the forward lookup (ie example.com). If you're using any sort of management system it should keep you on the straight.