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Forward and Reverse DNS Entries

When sending direct, AutoMSW acts as the sending mail server to send your emails.  Many receiving mail servers will perform a reverse DNS lookup on the IP address of the sending mail server, and make sure it matches the domain name of that mail server.  If it does not match, the receiving mail server may refuse connection.  Anti-spam software may also do reverse DNS lookups before delivering your email to the recipient.

Reverse DNS is the process of taking an IP address and looking up the name associated with that IP address.  A properly configured sending mail server should have a reverse DNS entry that matches the domain name of the server.  A good site to learn about this, and do various lookups is Network-Tools.com and Reverse DNS Lookup.  As an example, if your ISP was Earthlink, you could find out that one of the IP addresses for smtp.earthlink.net is 209.86.93.203 by doing a "Forward DNS Records Lookup" on the name smtp.earthlink.net, and look for the A record, which shows the IP address.  When this mail server delivers mail the receiving mail server would do a reverse DNS lookup on 209.86.93.203, and find that this IP address does indeed belong to the top level domain earthlink.net, and therefore it would accept the email.  This process essentially verifies that the sending mail server actually is who it says it is.

When sending direct you want to have a matching forward and reverse DNS entry.  This means you have a rDNS entry assigning a name to the static IP address you're sending from.  You also want an A type DNS record that assigns this name to your static IP address.  AutoMSW should be configured to send using this same name.  The "from" email address you send from should be for the same domain.  Examples:

rDNS: <static IP> resolves to the name automsw.mycompany.com
DNS: A type record that shows automsw.mycompany.com points to <static IP>
System Name: automsw.mycompany.com
From email: support@mycompany.com

The above examples used automsw.mycompany.com, but you can use anything as long as the top level domain part (mycompany.com) matches the email you are sending from.  You want to pick a name that isn't being used already for something else on your domain, so it can be <anything>.mycompany.com.

Setting a forward DNS entry is done through your web hosting company, or whoever is running the DNS servers for your domain.  Setting a reverse DNS entry is done by your ISP that provides the static IP address you're sending from.

See Also
Static IP Address
IP Address Reputation
How to DKIM Sign Emails
General Bulk Email Sending Tips
Direct Send Specific Sending Tips

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