When I run a dns check at www.dnsreport.com on any of our Cpanel domain names, I always notice the following error message....
WARNING: One or more of your mailservers is claiming to be a host other than what it really is (the SMTP greeting should be a 3-digit code, followed by a space or a dash, then the host name). If your mailserver sends out E-mail using this domain in its EHLO or HELO, your E-mail might get blocked by anti-spam software. This is also a technical violation of RFC821 4.3 (and RFC2821 4.3.1). Note that the hostname given in the SMTP greeting should have an A record pointing back to the same server. Note that this one test may use a cached DNS record.
myfakecustomer.com claims to be host ns.myfakeserver.net [but that host is at 207.55.55.55 (may be cached), not 207.55.55.101].
Whereas, 207.55.55.55 is the ns1 IP #
&
Whereas, 207.55.55.101 is the IP associated with the customer's domain name
So, since a reverse dns check will show the customer's IP #, and not the IP # that is reported by the email in the HELO section of the header, some companies will catch these emails in their spam filter (Comcast is one of them).
Is it possible to make the HELO in an email match a reverse lookup on a customer's email?
The HELO is currently the server IP # and a receiving server's reverse lookup will show the account IP #. (Consider that a customer has a dedicated IP, for example.).
WARNING: One or more of your mailservers is claiming to be a host other than what it really is (the SMTP greeting should be a 3-digit code, followed by a space or a dash, then the host name). If your mailserver sends out E-mail using this domain in its EHLO or HELO, your E-mail might get blocked by anti-spam software. This is also a technical violation of RFC821 4.3 (and RFC2821 4.3.1). Note that the hostname given in the SMTP greeting should have an A record pointing back to the same server. Note that this one test may use a cached DNS record.
myfakecustomer.com claims to be host ns.myfakeserver.net [but that host is at 207.55.55.55 (may be cached), not 207.55.55.101].
Whereas, 207.55.55.55 is the ns1 IP #
&
Whereas, 207.55.55.101 is the IP associated with the customer's domain name
So, since a reverse dns check will show the customer's IP #, and not the IP # that is reported by the email in the HELO section of the header, some companies will catch these emails in their spam filter (Comcast is one of them).
Is it possible to make the HELO in an email match a reverse lookup on a customer's email?
The HELO is currently the server IP # and a receiving server's reverse lookup will show the account IP #. (Consider that a customer has a dedicated IP, for example.).