|Every SOHO Router I've ever worked on came preconfigured using the Class C private IP range: 192.168.0.0|
I've never seen one that used Class B.
Regardless, for all LAN computers to communicate with each other, they all need to be in the same subnet.............period, full stop.
Whether you're statically assinging TCP/IP settings or letting DHCP do it, this is the only way. If you put all in the same subnet and they have issues communicating with each other then something else is wrong. As long as all computers in the LAN can ping each other, the network is fine.
Your server is in a completely separate subnet from all the LAN computers. If you wish to have the LAN PC's and the server communicate, you need to give the server an IP in the same subnet as the rest. If you wish to have the server also have internet access, you give it the LAN IP of the router as it's Default Gateway and DNS settings.
Example using your IP addressing scheme:
DHCP Scope = 172.16.1.100 to 172.16.1.199
All clients should get their IP's from DHCP unless they are providing a resource for the rest. If they are, then statically assign IP's not in the scope so as to avoid duplicate IP's. Statically assigned settings should include the same DG and DNS IP's as above.
Once done, all clients should communicate and have internet access. If for some reason you don't want a particular client PC to have internet access, but still maintain LAN access, you statically assign TCP/IP settings to it and leave DG/DNS blank.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.