Block Outlook externally - Exchange Online/On-Premises

[Kavindu Asanga Dayananda]

Hi

We have a hybrid (Exchange 2016) with Exchange Online and wants to block/restrict users connecting Outlook, outside of our network.

What options do we have to achieve this?

Regards,

Kavindu

[#2]

If your mailboxes are in Exchange Online, then the best option is Conditional Access. Pretty much the whole idea of cloud services is that you can access them from anywhere. If the mailboxes are on-premises, it should be simple to block access to Exchange from outside your network

[#3]

Thanks Dan,

But how do you think we can do that for Exchange on-premises?

[#4]

The simplest is to block any traffic destined for Exchange servers at the perimeter firewall