Briefly define the following codes currently assigned to the

Briefly define the following codes, currently assigned to the ICMP Destination Unreachable type number: Code 2: Protocol Unreachable, Code 3:Port Unreachable, and Code 5: Source Route Failed

Solution

ICMP error codes
Code 2: Protocol Unreachable
Description:
The IP datagram contains type of protocol to start a service .
The host or router sends the message to indicate that the protocol
set in the IP header is un reachable.

Code 3: Port Unreachable
Description :
When host sends a message with IP header that contains type of process to initiate
with the other host in the network.Then the host (receiving side host or router) sends
a message if that process or service is not started at it side.

Code 5: Source Route Failed
Description:
When a router finds that the original data packet contains strict or loost source routing path,
then the router sen sends this ICMP reply to indicate that the router cannot send the packet
due to its source quench.