Network Theory - TCP operations - IPv4 and IPv6 PMTU
3 important questions on Network Theory - TCP operations - IPv4 and IPv6 PMTU
What is the icmp message type 3 code 4?
ICMP message destination unreachable and fragmentation needed
How can the MTU be discovered?
In IPv4 PMTU, a host sends a packet with the DF option.
Any device inthe path of the packet with a smaller MTU than the packet cannot process the packet and will therefore drop it and send back an ICMP message of fragmentation needed and include its MTU.
The host can use this information to adjust its MTU appropriately. This is repeated until the packet reaches end destination
What IPv6 message is sent back when MTU is to big?
The question on the page originate from the summary of the following study material:
- A unique study and practice tool
- Never study anything twice again
- Get the grades you hope for
- 100% sure, 100% understanding
![Trustpilot Logo](/images/design_2020/lp/clp-trustpilot-en.png)