Debian Jessie 3.1.5 I can not send email to any AT&T or BellSouth addresses. If I send an email from a BS network I get: "Failed to transport message. xx.xx.xx.xx Host unreachable" The host is up and reachable. ============================================ Per AT&T We have received a request for this server to be removed from our black-list. Upon testing the submitted IP address, we have determined that Reverse DNS is generic or not setup correctly. Please configure a unique pointer record (one that matches your server's A record.) Once this Reverse DNS issue has been resolved, please forward a copy of the returned message, including the IP address to be removed to us at [email protected]. We can then process your request in an efficient manner. Regards, AT&T Postmaster Chief Security Organization [email protected] https://www.att.com/esupport/postmaster/ ====================================================== https://mxtoolbox.com/diagnostic.aspx shows the following --------------------------------------------------------------------- 220 mr1.mriservice.com ESMTP Postfix (Debian/GNU) Test Result SMTP Valid Hostname Reverse DNS is not a valid Hostname SMTP Reverse DNS Mismatch OK - xx.xx.xx.xx resolves to mydomain1.com, server1.mydomain.com, mydomain2.com, mydomain3.com, mydomain4.com, mydomain5.com, mydomain6.com, mydomain7.com, mydomain.com SMTP Banner Check OK - Reverse DNS matches SMTP Banner SMTP TLS OK - Supports TLS. SMTP Connection Time 0.651 seconds - Good on Connection time SMTP Open Relay OK - Not an open relay. SMTP Transaction Time 2.528 seconds - Good on Transaction Time ------------------------------------------------------------------------------------ DNS Zone Records A * xx.xx.xx.xx 0 3600 A mail xx.xx.xx.xx 0 3600 A mydomain.com. xx.xx.xx.xx 0 3600 A www xx.xx.xx.xx 0 3600 MX mydomain.com. mail.mydomain.com. 10 3600 NS mydomain.com. mr1.mydomain.com. 0 3600 NS mydomain.com. mr2.mydomain.com. 0 3600 PTR xx.xx.xx.xx mydomain.com 0 3600 TXT mydomain.com v=spf1 mx a ~all 0 3600 How do I fix this failure to communicate with ATT and BS? Thanks for your help
Contact the party that gave you that IP number. Ask them to change the reverse DNS PTR record to point to your mail server host.
Thanks for the reply. My host has such a portal. I have several IP addresses. Would the mail server host be server1.mydomain.com, mail.mydomain.com or mydomain.com?
DNS records are cached, you may have to wait 24 hours. and the correct value for the reverse record is the hostname of your server and not the domain name of your email domain.
Thanks for the reply. My problem is that I am not sure if I am entering the correct server value. Should I use server1.mydomain.com or simply mydomain.com for the rDNS. Do I need a rDNS foreach IP address used by server1.mydomain.com?
Here is how I setup mine: We own a range of IPs from Arin which is routed to the datacenter where our service is. first, I have created NS record for the authoritative, assume the IP is as follows: x1.x2.x3.x4 Zone: x3.x2.x1.in-addr.arpa. Nameserver hostname: auth2.dns.datacenter_provider.com. Second, I created PTR record as follows: Name: x4 Canonical Hostname: srv1.domain.com Not sure if this is the best setup but it is working. Good luck,
I have 5 IP addresses. I removed all the PTR and Text records from all of the domain names on one of my IP addresses and I still can not send email to or from an AT&T network. IP address iare not on any RBL lists.
mxtoolbox.com displays Reverse DNS is not a Valid Hostname What is wrong with my DNS records and how do I see what hostname is being returned? A * xx.xx.xx.xx 0 3600 A mail xx.xx.xx.xx 0 3600 A mydomain.com. xx.xx.xx.xx 0 3600 A www xx.xx.xx.xx 0 3600 MX mydomain.com. mail.mydomain.com. 10 3600 NS mydomain.com. server1.mydomain.com. 0 3600 NS mydomain.com. server2.mydomain.com. 0 3600 PTR xx.xx.xx.xx mail.mydomain.com 0 3600 TXT mydomain.com v=spf1 mx a ~all 0 3600
I think that rDNS must be changed by your ISP. In my case I had to request to them to change the rDNS name. Also, if you have a subnet from your Internet provider, you can request to them to delegate to you the rDNS management.
Conductive needs to clearly tell us if he was given the power to declare rDNS or not? In the meantime, I think the PTR record should be the last octet only, meaning PTR xx mail.mydomain.com 0 3600
This is probably where my problem starts. How is a reverse zone set up and/or how does it differ from a reverse zone. More specifically how do I set them up? It appears that I have the power to enter any rDNS value necessary. The Portal looks like this. Manage RDNS Reverse DNS Records for xxx.xxx.xxx.168/29 IP Address Hostname xxx.xxx.xxx. ??? server.example.com (Example) XXX.XXX.XXX.170 mydomain.com (Current Value) Does this mean that I need to make a subdomain mail.mydomain.com. Do I delete my domain record A mail xxx.xxx.xxx.170 0 3600
It means that you have to delete every PTR records from site zone, and create a special DNS zone only for PTR records. Also you can try to buy the ISPConfig manual, it's only 5 EUROs, has all the info you need.
