The reason that the IP header and first 8 bytes of a datagram data in the error reporting ICMP message is included...
By submitting your email address, you agree to receive emails regarding relevant topic offers from TechTarget and its partners. You can withdraw your consent at any time. Contact TechTarget at 275 Grove Street, Newton, MA.
is to help you understand what conditions might have created the error message. For example, destination unreachable messages have a few causes that the original header might provide. Sometimes the source IP address is very helpful in determining which router interface the ICMP ping message was sent. Sometimes it's not the interface you would think! Or you might have entered the wrong destination IP to ping. This would be helpful in relentlessly pursuing network or host unreachable messages.
For protocol unreachable messages, having the first bytes of the payload would be the TCP source and destination port. This would provide insight into which application port it was trying to connect to.
Having this information is also relevant to source quench and TTL expiration messages to troubleshoot why potential problems might be occurring with routing loops, etc. So there are several reasons why the original IP header and first 8 bytes of the payload might be useful.
For additional information and a more complete explanation, I did a little research and like Chapter 32 of Charles M. Kozierok's The TCP/IP Guide, which I found available through Google books.
Nothing like a little light midnight reading material to inspire creativity!
Dig Deeper on Network Administration
Related Q&A from Lindi Horton
Lindi Horton explains how to provide the fastest Internet sharing speed to a client when many users are trying to access the internet as well as ...continue reading
Network Administration expert, Lindi Horton provides her expertise on advantages of DNS, and provides an example of a reliable and flexible DNS ...continue reading
Network administration expert, Lindi Horton answers a query regarding file server troubleshooting. She explains potential reasons for file server ...continue reading
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.