We are in the final steps of a process to upgrade from Exchange Server 2010 to Exchange Server 2019 with Edge Transport. We first migrated to Exchange 2016 with an Edge Transport server (using Exchange 2016), with the Edge Transport server domain joined and inside the subnet of the Exchange server. Mail flowed properly to the new Exchange Server 2016, using the Edge Transport server.
We then created an Exchange 2019 server and successfully migrated all mailboxes to the new server. We also created a new Edge Transport server (using Exchange 2019) and placed the new Edge Transport server in a DMZ. The new Edge Transport Server is not domain joined. We have firewall rules allowing 25/TCP, 50636/TCP, 587/TCP and 2525/TCP into the DMZ and through to the LAN zone. We've also made 53/UDP+TCP allowed from DMZ to LAN to allow DNS lookup. We've synced both Edge servers with AD, and NAT is currently pointed to the 2016 Edge Transport server.
When we change NAT from the 2016 Edge Transport server to the new 2019 Edge Transport, mail gets stuck in the Queue on the Edge 2019 server. We've updated the hosts file on the 2019 Edge Transport server to manually input the DNS entries, and re-subscribed the Edge Transport server, but that didn't help.
We have both Edge Transport servers subscribed to both mail servers, but when we shut down the 2016 Exchange server, mail stops flowing, despite mailboxes being on the 2019 server. There appears to be some dependence on the 2016 Exchange server, but we are unable to resolve where this dependence is.
We are seeking a freelancer to assist us in fixing the mail flow so the NAT can point to the new 2019 Edge Transport server in the DMZ, and mail can flow to the new 2019 Exchange server. We also need to remove the dependence on Exchange 2016 so we can shut down this server.
About the recuiterMember since Sep 30, 2017 Christian
from New York, United States