How many users could be access internet via XG125?

Its not that easy.

User numbers are nowadays only a small factor. A User can consume a entire appliance, depending on what he is doing. If your users only browser in the internet and checking emails or they are working within cloud database services, there is a big difference. 

It is likely you need to verify, if the desired appliance meets your network requirements. 

https://www.sophos.com/en-us/medialibrary/PDFs/factsheets/sophos-xg-series-appliances-brna.pdf

Page 12. 

Does the performance numbers are, what you are looking for? 

Thanks.

The XG125 for brower and mails checking. 

Brgds

LIu Wei

Thanks.

The XG125 for brower and mails checking. 

Brgds

LIu Wei