Forum Discussion
Integrate mail system between O365 and mail system on-premise
Dear all friends and experts From my customer requirements. They have a system email on-premise ( I do not know what is their product of their mail system ( exchange or open resources ..). ...
You need to have Exchange on premise to have a Hybrid environment.
You may have a look at this.
https://docs.microsoft.com/en-us/exchange/exchange-hybrid