Two pings were issued from a host on a local network. The first ping was issued to the IP address of the default gateway of the host and it failed. The second ping was issued to the IP address of a host outside the local network and it was successful. What is a possible cause for the failed ping?

The scenario you’ve described is somewhat unusual because typically, if a ping to the default gateway fails, pings to external hosts should also fail, as the default gateway is the local network’s access point to outside networks. However, given the situation, one plausible explanation for the failed ping to the default gateway but successful ping to an external host could be:

• Security rules are applied to the default gateway device, preventing it from processing ping requests. Some network devices, including default gateways, can be configured with security rules or firewalls that block certain types of traffic. In this case, the default gateway could be configured to ignore or block ICMP packets, which are used for ping commands, from hosts within the local network.

The other possibilities you mentioned are less likely given that a ping to an external host was successful:

• The default gateway is not operational: If this were the case, the host would not be able to access any external network, including the successful ping to an external host.
• The default gateway device is configured with the wrong IP address: Again, if this were the case, the host would not be able to route packets to external networks.
• The TCP/IP stack on the default gateway is not working properly: Similar to the first point, this would typically prevent all external network communication.

Therefore, the most likely scenario given your description is that the default gateway has security rules in place that specifically block ping requests from the local network.