2
rDNS lookup failing for emails sent to aol.com, charter.net, att.net
Problem reported by Kenneth Horne - 12/11/2014 at 8:58 AM
Submitted
Hello all!  We recently migrated to a new server and reinstalled SmarterMail.  All of our firewall and DNS settings were transferred over from the old setup, and the only thing that changed was our IP address block.  Since the reinstall of SM, we have received a lot of rDNS lookup failures from multiple domains.  
 
We have spoken to our ISP, our web server host, and tried to bring in AOL on this.  Our ISP told us that everything is fine on thier end, AOL gave us this link http://postmaster.aol.com/cgi-bin/plugh/rdns.pl to check our DNS and it matches our domain correctly, and our web host found a missing PTR record that has now been added.  
 
Are there any settings in SM that could be causing this?  Our hostname and DNS IPs match up with what they should be.  I can post the headers for the failures if needed.  Thanks

1 Reply

Reply to Thread
0
Bruce Barnes Replied
RDNS must be added by the IP provider for your network. In a hosted situation, then you contact your hosting company to map the RDNs. PTR records and RDNS are not the same thing. Remember, too, that CNAMES are PROHIBITED for all MX records. They must point directly to a hostname/IP address combination.
Bruce Barnes
ChicagoNetTech Inc
brucecnt@comcast.net

Phonr: (773) 491-9019
Phone: (224) 444-0169

E-Mail and DNS Security Specialist
Network Security Specialist

Customer Service Portal: https://portal.chicagonettech.com
Website: https://www.ChicagoNetTech.com
Security Blog: http://networkbastion.blogspot.com/

Web and E-Mail Hosting, E-Mail Security and Consulting

Reply to Thread