Error-detection

The ability for a protocol or a program to determine that something went wrong.

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Verifying Conectivity

Ping : Internet Control Message Protocol

• Internet Control Message Protocol
  ICMP is mainly used by a router or remote host to communicate hy transmission jhas failed back to the origin of the transmission.
  

1. Type : 8 bits long, specifies what type of message is being delievered.
2. Code : 8 bits long, Indicates a more specific reason for the message than just the type.
3. Chceksum : 16 bits
4. Rest of the header : This field is optionally used by some of the specific types of types and codes to send more data.
5. Data payload : The payload for an ICMP packet exists entirely so that the recipient of the message knows which of their transmissions cause the error being reported. It contains the entire IP header, and the first 8 bytes of the data payload section of the offending packet/.

Ping

Ping let's you send a special type of IMCP message called an echo request.
ICMP echo request -> "Hey, are you there?"
If the destination is able to communicate on the network,. it will send back an ICMP echo reply message type.

Traceroute

Traceroute is an utility that lets you discover the paths between two nodes, and gives you information about each hop along the way.

Testing Port Connectivity

Tools letting you know if things are working at the transport layer

• Netcat (linux and mac os)

• Test-NetConnection (windows)