we have an in premesis exchange 2013 with our own domain but some users prefer to work with gmail and send mail as our domain email address.we tried to setup our exchange server for smtp authentication with gmail but with no luck.we are trying to find a sulotion for this and one idea was to migrate these users to office 365 and then use the smtp server of 365 for smtp authentication with gmail.
My question is if this sulotion will work since we are not planing to modify the mx record that points to our exchange server.
any other suggestions for solutions will be welcomed
Thanks