The problem is a subnet mismatch . The web server is using 255.255.255.0 , which places it in the 192.168.1.0/24 network. The database server is using 255.255.255.128 , which places 192.168.1.201 in the 192.168.1.128/25 network. So even though both addresses begin with 192.168.1, the two systems are not treating the network boundaries the same way.

That creates a Layer 3 communication issue because one host may believe the other device is local while the other host may treat traffic differently based on its smaller subnet. In a normal server segment like this, both systems should agree on the same mask if they are intended to be on the same network.

Changing the database server’s subnet mask to 255.255.255.0 fixes that inconsistency immediately. Then both servers and the firewall interface are using the same local network definition, and traffic can be handled properly.

The other options do not solve the real issue. Changing the firewall to /25 would break consistency for the rest of the segment. Pointing the database server to 1.2.3.4 is incorrect because that is outside the local subnet and appears to be an upstream route. Changing the IP to 192.168.1.150 still leaves the wrong mask in place. The clean fix is A .