2. What icmp protocol
• Internet Control Message Protocol (ICMP) is a supporting protocol in
the Internet protocol suite
• It is used by network devices
• including routers
• the send error messages and operational information indicating
• ICMP differs from transport protocolssuch as TCP and UDP in that it is not
typically used to exchange data between systems
3. Technical details
• ICMP is part of the Internet protocol suite as defined in RFC 792
• ICMP messages are typically used for diagnostic or control purposes or generated
in response to errors in IP
4. Datagram structure
• Type :ICMP type, see Control messages.
• Code : ICMP subtype, see Control messages
• Checksum :Error checking data, calculated from
the ICMP header and data, with value 0
substituted for this field. The Internet Checksum
is used, specified in RFC 1071
• Variable
6. Ping
• Ping is a basic Internet program that allows a user to verify that a particular IP
address exists and can accept requests.
• Ping is used diagnostically to ensure that a host computer the user is trying to reach
is actually operating. Ping works by sending an Internet Control Message Protocol
(ICMP) Echo Request to a specified interface on the network and waiting for a
reply. Ping can be used for troubleshooting to test connectivity and determine
response time.
• Check ip or domain
• Ping 192.168.1.1
• Ping www.google.com
7. traceroute
• For most of us, phone calls and Internet
connections seem to happen
instantaneously. It feels as if our computer
has a direct line to our favorite websites.
Web pages load so fast that it seems that
we must have a direct connection to any
computer, even one across the country.But
we don't.
8. traceroute
• The traceroute identifies each computer/server on that list and the amount of
time it took the data to get from one computer to the next. If there was a hiccup
or interruption in the transfer of data, the traceroute will show where along the
chain the problem occurred.
9. Traceroute How data travels.
• Each computer on the traceroute is identified by its IP address, which is the nine-
digit number separated by periods that identifies that computer's unique
network connection.
•
n the past, computer hackers would routinely use traceroutes to map how
information moved within a company's computer network and then focus their
attacks on certain computers. To combat that security threat, some networks will
not allow you to perform a traceroute.
10. Traceroute How to run a traceroute
• Windows command line tracert tracert www.google.com
• Unix Traceroute Traceroute www.google.com
