Question

You manage a network of multiple subnets connected to the Internet.A user reports that she can't access the Internet. You investigate the problem and find that she can access all hosts on the private network, but no hosts on the Internet. Which of the following is likely the cause of the problem?

a. Missing default route on a router.
b. Incorrect DNS settings on the user's device.
c. Firewall blocking outgoing traffic to the Internet.
d. Subnet mask misconfiguration on the user's device.
e. ISP connectivity issues.
f. VLAN misconfiguration on the switch.
g. Incorrect proxy settings on the user's device.

Answer 1

The inability to access the Internet while being able to communicate within the local network likely indicates a missing default route, incorrect DNS settings, or a firewall blocking outgoing traffic.

Step-by-step explanation:

If a user can access all hosts on the private network but cannot access the Internet, the likely cause is one of the network configurations related to external network access. A possible issue could be the missing default route on a router (a). Without a default route, the router doesn't know where to send traffic destined for networks it doesn't have in its routing table, which typically includes the Internet. Another possibility could be incorrect DNS settings on the user's device (b), which can prevent domain names from being resolved to IP addresses. Thirdly, a firewall blocking outgoing traffic to the Internet (c) could also be the cause if certain rules are set to restrict Internet access. However, since the user can access local hosts, issues with the subnet mask (d), ISP connectivity (e), VLAN configuration on the switch (f), or incorrect proxy settings (g) are less likely because these problems would typically prevent local network access as well.