How do I change the outgoing IP address for email?

Question

How do I change the outgoing IP address for email?

Answer

Exim sends all mail from the server's primary IP address by default. You can configure it to send from a different IP for all accounts, or a different IP for each domain.

1. Log in to WHM as the root user.
2. Navigate to Exim Configuration Manager.
3. Make sure the option Reference /etc/mailips for outgoing SMTP connections is enabled.

4. In SSH, edit the /etc/mailips file and add the following line, replacing the IP with the address from which outbound messages for all accounts should be sent. If you are using a system behind a NAT configuration, make sure to enter the private IP address:

   CONFIG_TEXT: *: 10.0.0.15

   You can also add an IPv6 address:

   CONFIG_TEXT: *: ::1

   If you have multiple IPs and would like to specify a different IP for some domains, you can do so by specifying a domain along with an IP instead of a wildcard:

   CONFIG_TEXT: domain1.tld: 10.0.0.8
   domain2.tld: 10.0.0.17
   *: 10.0.0.15

5. If adding an IPv6 address, you will need to create the following touch file to have Exim prioritize the IPv6 networking device:

   # touch /var/cpanel/exim_ipv6_sort_bias

For additional details and more customization options, see our documentation here:

How to Configure the Exim Outgoing IP Address