Hi,

that depends how you would like to Enroll your Devices.

When you enroll over Google with Silent Enrollment -> Yes

You can Enroll your Deive by Scanning an QR Code or do a Manually Enrollment with manually Downloading the Agent form the Server.

It Depends what Device and Andriod Version are you trying to enroll.

Hello,

i am enrolling an android 8.1 device using enterprise Android rule 

If you have configured an Enterprise Binding and you want to distribute Managed Play applications then the devices will need to have access to Play.google.com/work. If you have no need for Managed Play and you want to distribute all apps directly on devices via Package or File Sync then you can setup your enrollment rule to Skip the service account creation during enrollment. 

If you are using the Enrollment ID for enrollment then devices will need to have internet access to the SOTI enrollment service in order for that lookup to translate to an Enrollment URL. You can just use the Enrollment URL directly instead of the ID if you want to bypass that enrollment service. 

In other words, you need internet access if you want to use certain features like Managed Play and the Enrollment service but you  can get away without it depending on your use case. 

In addition to what Matt outlined in his post, your devices need to access Samsung server for ELM license check if they are from Samsung.  Your devices might also need to access the OEM server to check/upgrade device firmware from time to time (or at least just before enrollment if the firmware are known to be outdated).