Forwarders when using Exchange server

[Charles Pedro]

I have Exchange Server 2016 setup with the same registered domain name in cPanel

Exchange Server 2016 Setup
Server Name: SVRA
AD Domain Name: removed.tld
Full computer name: SVRA.removed.tld
External Interface IP (public): 172.10.1.1

cPanel Detail
Registered Domain Name: removed.tld

Zone Records:
removed.tld. 14400 IN A 1.2.3.4 (cPanel IP Address)
webmail.removed.tld. 14400 IN A 172.10.1.1
autodiscover.removed.tld. 14400 IN A 172.10.1.1

removed.tld. 14400 IN MX Priority: 0 Destination: removed.tld
removed.tld. 14400 IN MX Priority: 0 Destination: webmail.removed.tld

mail.adsvr.com. 14400 IN CNAME removed.tld
removed.tld. 14400 IN CNAME removed.tld
owa.removed2.tld. 14400 IN CNAME webmail.removed.tld

Above are the configuration of the Exchange Server and cPanel Setup
Everything is working. Users can send and receive both internal and external mails except
mails coming from Gmails/Yahoo (i.e. public mails) are bouncing back.

Scenarios:
All email accounts are hosted on the Exchange Server 2016.
Now we want to create forwarder with the following conditions
A. All mails will be access through Outlook Web Access when Exchange Server is Online
B. Some selected email accounts should access their mails through cPanel Webmail when the Exchange Server is offline

I tried creating a forwarder like this

Address to Forward: [email protected]
Destination Forward to Email Address: [email protected] (since I am using the registered domain name for my Exchange Server 2016)

It worked the first time I created it but some few minutes later, mails are either bouncing back or stay in the cpanel when Exchange Server is Online.


1. Please How can I achieve scenerios A and B? This is my first priority to acchieve
2. How do can users receives mails from public domain?

Thank you
Charles Pedro

 

[cPanelMichael]

Hello @Charles Pedro,

The configuration you are attempting to implement isn't supported. You're likely going to encounter multiple issues during the setup attempt because cPanel & WHM is not designed to work as a failover/clustering solution for email (there's no supported method of syncing the email data). I recommend reaching out to a system administrator or posting to the Exim User's mailing list for assistance with this type of setup:

System Administration Services | cPanel Forums
Exim-users Info Page

Thank you.

 

[Charles Pedro]

Ok. I have tried changing the Email Routing from Local to Remote inorder to achieve this, but the mail bounce back to the sender with this error message:

<[email protected]>: host example.com[23.111.xxx.xxx]
    said: 550-Please turn on SMTP Authentication in your mail client.
    550-sub5.mail.domain.com (xxxxxx-a140.g.domain.com)
    550-[208.113.xxx.xxx]:58381 is not permitted to relay through this server
    550 without authentication. (in reply to RCPT TO command)

I am just wondering if I could include an MX record for the localhost A record on the cpanel so that the mail can be routed to the cpanel mail server if the remote is offline.

What is the function of the localhost with IP 127.0.0.1 on the cpanel?

How do I route the mail to the cpanel since I have set the Priority of the MX records as follows:

example.com. 14400 IN MX Priority: 0 Destination: example.com
example.com. 14400 IN MX Priority: 0 Destination: webmail.example.com

Or what does this error mesage implies? I have both account (i.e. [email protected]) created on the cpanel as well as on the exchange server.

Thanks

 

[cPanelMichael]

Hello Charles,

Can you provide more information on the specific scenario you'd like to setup the MX records to address? For instance, is this longer the same configuration that you noted in your original post?

Thank you.