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Internet layer basically provides the fault rectification and routing of a packet that which ever the best and shortest route it would take and also Logical addressing is performed on same layer
This is complete bollocks. First, ICMP does not use a port since it does not have a place for a port. It is encapsulated with an IP datagram only. You will find the port option only on UDP and TCP datagrams. To block ICMP echo, you would explicitly block the type and code.People who do think that ICMP somehow uses port 7 (the old echo service where it would echo every character you sent to it) should not be in networking and should be shot.If you do not agree with what I have said, look at the structure of an IP datagram and of an ICMP datagram. The ICMP is encapsulated in the IP datagram and then the IP datagram into whatever the particular media needs to form the frame.
http://www.ingate.com/files/422/fwmanual-en/xa10285.html
The Internet Control Message Protocol (ICMP) is one of the main protocols of the internet protocol suite. It is used by network devices, like routers, to send error messages (ping-unreachable) . It is different from transport protocol such as TCP and UDP which typically used to exchange data. And I don't think that it uses a port. Good question you got there. Thanks a lot.
