Do I need to change rDNS or not?

chris0147

Well-Known Member
Aug 28, 2015
104
2
68
London
cPanel Access Level
Root Administrator
Hi all,

I need some help, I have been advised that I need to change the rDNS to match it with the smtp banner as they both are not matching. On my main server, the rDNS is: server.mydomain.com. It's pointing to the IP 104.xxx.xxx.xx. It is the same for mail.mydomain.com which is also pointing to the IP 104.xxx.xxx.xx as I have added the A record. When I send the email it will show mail.mydomain.com, so the rDNS (server.mydomain.com) and the mail domain (mail.mydomain.com) is not matching. I am not sure if I do I need to change the rDNS or not?

How I can find out what is my smtp banner?

If I do need to change the rDNS, do I need to change the rDNS from server.mydomain.com to smtp.mydomain.com or mail.mydomain.com?

If I change the rDNS from my hosting provider panel, do I need to change the cpanel hostname as well or not?

Any advice would be much appreciated.

Thanks in advance.
 
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RoseHosting

Active Member
PartnerNOC
Jan 3, 2003
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You can go to mail-tester.com and send an email to the email address you see in mail-tester.com, then follow the instruction there. You will be provided with some recommendations regarding your email deliverability issues, including the rDNS.
 
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cPanelLauren

Product Owner
Staff member
Nov 14, 2017
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In the majority of cases, the PTR should match the hostname of the server, and the contents of /etc/mailhelo should match what is set for the PTR record. All of these should reference the same host.
 

chris0147

Well-Known Member
Aug 28, 2015
104
2
68
London
cPanel Access Level
Root Administrator
Thanks for the advice guys, I have checking on /etc/mailhelo and it show empty so what I need to do?

I sent an test email on mail-tester.com and the rDNS is server.mydomain.com

Here is the details:
  • HELO: server.mydomain.com
  • rDNS: server.mydomain.com


Does the rDNS need to change and what about the HELO?

If I need to change the rDNS and HELO, can I leave my cpanel hostname as server.mydomain.com?

Please advise me as I need to know asap.
 

chris0147

Well-Known Member
Aug 28, 2015
104
2
68
London
cPanel Access Level
Root Administrator
We personally recommend checking the /etc/mailhelo file
you may need to check exim settings to make sure all users use the same banner
I have checking on /etc/mailhelo file and it show as empty. So when I sent the mail-tester email it show:

  • HELO: server.mydomain.com
  • rDNS: server.mydomain.com


Do you know what I need to do?

And where I can check on exim setting to make sure that all users use the same banner?
 

chris0147

Well-Known Member
Aug 28, 2015
104
2
68
London
cPanel Access Level
Root Administrator
In the majority of cases, the PTR should match the hostname of the server, and the contents of /etc/mailhelo should match what is set for the PTR record. All of these should reference the same host.
Can you please be more clarify please?

I dont understand what you mean the PTR should match the hostname of the server? you mean my cpanel hostname or what?
 

CarlosManceraK

Active Member
PartnerNOC
Apr 12, 2018
27
1
3
Aguascalientes Mexico
cPanel Access Level
Root Administrator
I have checking on /etc/mailhelo file and it show as empty. So when I sent the mail-tester email it show:

  • HELO: server.mydomain.com
  • rDNS: server.mydomain.com


Do you know what I need to do?

And where I can check on exim setting to make sure that all users use the same banner?
If your host is server.mydomain.com, your /etc/mailhelo file should contain something similar to "*: server.mydomain.com"

Then point your Rdns to server.mydomain.com, after entering your rdns, run the command "host your_ip" and verify it has something like "X.X.X.X.in-addr.arpa domain name pointer server.mydomain.com".
 

chris0147

Well-Known Member
Aug 28, 2015
104
2
68
London
cPanel Access Level
Root Administrator
If your host is server.mydomain.com, your /etc/mailhelo file should contain something similar to "*: server.mydomain.com"

Then point your Rdns to server.mydomain.com, after entering your rdns, run the command "host your_ip" and verify it has something like "X.X.X.X.in-addr.arpa domain name pointer server.mydomain.com".
Well I want to use something is like smtp.mydomain.com. Is it recommended to use smtp.mydomain.com instead of server.mydomain.com when I change in rdns and mailhelo as well?

When I change rdns and mailhelo, do I have to change my cpanel hostname or not?

I want to use server.mydomain.com as cpanel host name while use smtp.mydomain.com as the rdns so I can use it for send and receive my emails.
 

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
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The best way to do this would be to have all of the sources match. If you're wanting to use smtp.domain.tld then I'd suggest

1. assigning a specific IP for this
2. adding a ptr record for smtp.domain.tld
3. use the following to configure this for /etc/mailips and /etc/mailhelo How to Configure the Exim Outgoing IP Address | cPanel & WHM Documentation

But this is pretty complicated and requires maintenance.
 

chris0147

Well-Known Member
Aug 28, 2015
104
2
68
London
cPanel Access Level
Root Administrator
The best way to do this would be to have all of the sources match. If you're wanting to use smtp.domain.tld then I'd suggest

1. assigning a specific IP for this
2. adding a ptr record for smtp.domain.tld
3. use the following to configure this for /etc/mailips and /etc/mailhelo How to Configure the Exim Outgoing IP Address | cPanel & WHM Documentation

But this is pretty complicated and requires maintenance.

Thank you for the suggest, but you didnt say if I have to change my cpanel hostname as well?

I dont want to change the cpanel hostname from server.mydomain.com to smtp.mydomain.com. I hope I can still use the current cpanel hostname while I can change the rDNS and the mailips and the mailhelo as well.
 

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,296
1,271
313
Houston

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,296
1,271
313
Houston