Is there anything I need to consider when configuring the incoming filter in cPanel?

If you are using cPanel as hosting platform, please ensure that the following points are performed:

1

Make sure that the e-mail routing is set to Local Mail Exchange and does not use Auto Mail Exchanger.

If a non-local hostname is detected by cPanel, cPanel will recognize the domain as "remote" and will not accept any more mail for you.

2

Make sure that the catch-all function is disabled for your domains. You can do this as follows:

"Default Address" > "Discard the email while your server processes it by SMTP time with an error message"

3

Allow delivery through our servers. This allows you to bypass all sender, recipient, spam and forwarding checks and ensure proper delivery. To do this, add the IP addresses of our delivery servers under "Only-Verify-Recipient":

"Exim Configuration Manager" > "Basic Editor" > "Access Lists"

You can find a list of all IP addresses here. You can also enter the IP addresses directly into the following file:

/etc/trustedmailhosts

Please make sure that the IPs are not in /etc/skipsmtpcheckhosts but only in /etc/trustedmailhosts, otherwise the status of the domain may appear as "catch-all".

4

If you are using ConfigServer Firewall (CSF) within cPanel/WHM, it is recommended that you also store the IP addresses of the delivery servers there. You can add them at the following place:

/etc/csf/csf.ignore

5

Please restart the firewall after you have added the IP addresses.

6

Make sure that smtp_accept_max is set to the cPanel default setting (100).