Suppose a computer sends a packet at the network layer to another computer somewhere in the Internet. The logical destination address of the packet is corrupted. What happens to the packet? How can the source computer be informed of the situation?
Answers
Answer: In general if there is a problem in a Network bad enough to corrupt a packet at the transport layer 2 level, then the sender’s address is also corrupt. This is because the way a CRC checksum works. When a packet arrives malformed the checksum just tells the receiver the data is garbage, and the packet gets tossed. There is no way for an intermediate router to figure out the sender’s address at this point because the entire packet with both the sender’s and receiver’s address cannot be trusted, hence the packet is thrown out. As another commenter pointed out, TCP will retry based on the fact it did not receive an (ACK) , but this is just like waiting for a BUS that does not show up and calling an Uber , you will never know what happened to the bus.