A systems administrator is deploying a new physical server that will function as a web server in the perimeter network (DMZ). The administrator manually configures the network interface with the following settings:
IP Address: 10.100.100.50
Subnet Mask: 255.255.255.0
DNS Server: 8.8.8.8
The administrator confirms that the server can successfully communicate with other servers on the same 10.100.100.0/24 subnet. However, the server is unable to reach the internet to download necessary software updates. Which of the following configuration changes is MOST likely to resolve this issue?
Change the IP address, as it is an invalid APIPA address.
Change the subnet mask to 255.255.0.0.
Configure the default gateway address.
Assign the primary DNS server address to the internal corporate DNS.
The correct answer is to configure the default gateway address. A default gateway is a device, typically a router, that serves as an access point to other networks. When a server needs to send traffic to an IP address outside of its own local subnet, it sends that traffic to its configured default gateway. In this scenario, the server can communicate with devices on its local 10.100.100.0/24 subnet but cannot reach the internet, which is on an external network. This indicates that the server does not have a route to external networks, a problem solved by setting the default gateway address.
Assigning a different DNS server would not solve the problem. While DNS is required to resolve domain names to IP addresses, the fundamental issue here is network reachability, not name resolution. The server cannot reach any external IP address, which is a routing problem.
The IP address 10.100.100.50 is a valid private IP address as defined by RFC 1918 and is not an APIPA address. APIPA addresses are in the 169.254.0.0/16 range and are self-assigned when a device cannot contact a DHCP server.
The subnet mask 255.255.255.0 is a correct and standard mask for a /24 network, which is appropriate for the IP address assigned. It correctly defines the local network boundary.