I had this question after viewing Users on different subnet cannot access internal sharepoint site.
The SharePoint server is hosted in a data center with IP address 10.0.0.25 and the network mask for that server is 255.255.254.0 (/23). I can access it from hosts within that subnet.
We have a remote office connected with IP addresses 10.0.4.* (subnet 255.255.255.0 / 24). It is connected with in the same LAN segment through a firewall, since the entire network is /16 (255.255.0.0).
I can access EVERYTHING on the datacenter subnet from the remote office subnet EXCEPT SharePoint.