Internet Control Message Protocol Flashcards
When a network error occurs, the device that detects it needs a way to communicate this to the source of the problematic traffic. This is where __ comes in.
ICMP (Internet Control Message Protocol)
ICMP is mainly used by a ______ or ______ to communicate why a transmission has failed back to the origin of the transmission.
router, remote host
The first field of an ICMP packet that is 8 bits long.
Type field
Specifies what type of message is being delivered
ex. destination unreachable, time exceeded
The second field of an ICMP packet that is 8 bits long which indicates a more specific reason for the message than just the type.
Code field
(Example: The message type “Destination unreachable” can contain individual codes for more specific reasons like destination network unreachable or destination port unreachable)
The third field of an ICMP packet that is 16 bits long that detects corruption or lost data.
Checksum field
This field is optionally used by some of the specific types and codes to send more data.
Rest of head field
What does the data payload in an ICMP packet contain?
The payload exists entirely so that the recipient of the message knows which of their transmissions caused the error being reported.
This lets you send a special type of ICMP message called __
Ping
A Ping is used to test __
Network connectivity
This utility is used to show the route that is taken by data packets as they travel across the internet to their destination.
Traceroute
When the TTL field reaches zero, the packet is __ and an __ message is sent back to the __ host.
Discarded
ICMP Time Exceeded
Originating
A traceroute pings each __ on its way to the destination.
Router
The command for Traceroute in windows OS is __
tracert
A utility used to test connection at the transport layer.
Netcat (Linux)
Test-NetConnection (Windows)
The Netcat/Test-NetConnection tool is used to test __ connectivity.
Port
