We have come to the point where we are completely ready to change the MX records for all the domains. The process involved a lot of manual work but we split up the domains and managed to do it in a short amount of time. When we finished we ended up with all domains pointed to G Suite.
Once we completed the MX records change, we moved then to fixing all SPF records. Started with the primary domain there was not a lot to do. We just added the Google part of the SPF record to the existing one and we were all set.
After changing the MX records we found out about some issues in group permissions and other issues about bad forwarding settings between G Suite and Office 365 and managed to fix them all.
We also took a quick look about the progress of the … Read the rest “A story of a project: 3600 users to G Suite in 60 days! – Day 8: Changing MX records”