==== Required information ====
- iRedMail version (check /etc/iredmail-release):
0.9.7 Upgraded by Zhang Huangbin <zhb@iredmail.org> on Jul 13, 2017.
- Linux/BSD distribution name and version:
Ubuntu 16.04.2 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
MySQL
- Web server (Apache or Nginx):
Apache
- Manage mail accounts with iRedAdmin-Pro?
iRedAdmin-Pro SQL
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
Recipient address rejected: SMTP AUTH is
   required, or it is a spam with forged sender domain (in reply to RCPT TO
   command)
====

We are migrating from one server to a new iRedMail install. We need the domains to be active on both servers to migrate messages. We will be migrating the domains over time so we need to keep both servers online until all domains are off the old server.
I have added the old servers IP address to /opt/iredapd/settings.ph: MYNETWORKS
Given two domains, example.net and example .com with example.net setup on both the old server and the new server.
If I send a message from user@example.net to user@example.com I get the above bounce message.
I need to be able to have all domains configured on both the old server and the new server and have the new server accept all messages from the old server.
If I disable the example.net on the new server the emails to example.com arrive properly.
Besides MYNETWORKS, where else do I need "whitelist" the server I am migrating from?