IP Flashcards
What happens if everyone sets their packets to the fastest service in Type of Service?
The service becomes ineffective as all packets are treated equally
Why are fragments not commonly used anymore?
Fragments are not commonly used anymore because they create security risks, such as enabling DDoS attacks and packet reassembly vulnerabilities, which attackers can exploit to bypass security measures or disrupt networks.
What happens if an attacker sends unfinished fragments repeatedly?
The system buffers indefinitely leading to a DDOS attack
What is fragmentation in IP?
Breaking large packets into smaller ones to fit the MTU
(MTU (Maximum Transmission Unit) is the largest size of a packet that can be sent over a network without needing fragmentation.)
Where does fragmentation happen?
At networks with smaller MTU sizes
Where does packet reassembly happen?
Only at at the destination host (e.g., the client or server receiving the data).
What happens if one fragment is lost?
The entire packet must be retransmitted
What does MTU stand for?
Maximum Transmission Unit
What is the primary issue with fragmentation?
It is inefficient and unreliable
Does IPv6 support fragmentation?
No IPv6 does not support fragmentation
What does TTL stand for in IP?
Time To Live
What happens when a packet’s TTL reaches zero?
The packet is discarded and an ICMP error is generated
What is the default initial TTL value?
Commonly 64 hops but varies by system
Does IP guarantee delivery of packets?
No IP does not guarantee delivery
Does IP provide sequencing for packets?
No IP does not provide sequencing.
(it treats each packet independently and does not ensure they arrive in order)
Sequencing and reassembly of packets are handled by higher-layer protocols like TCP.
Does IP ensure packet reliability?
No IP does not ensure reliability
How large are IPv4 addresses?
IPv4 addresses are 32 bits long
What is the role of the IP header checksum?
To detect accidental corruption in the header
Does the header checksum improve security?
No it does not improve security
What are the fields in the IP header measured in?
They are measured in bytes
What is the typical size of an IP header without options?
Twenty bytes
What is the purpose of the Version field in the IP header?
To specify the version of the protocol
What does the IHL field in the IP header represent?
The length of the header in 32-bit words (aka 4 bytes)
(Internet Header Length)
What happens if the IHL field is greater than five?
It indicates that options are present in the header
Why are IP options generally removed by firewalls?
They are insecure and largely obsolete
(IP options are insecure as they can bypass firewalls, exhaust resources, and exploit outdated features, making them a target for attacks.)
What is the purpose of the Type of Service field?
It is used for tagging packets based on priority or security
Is the Type of Service field widely used today?
No it is not widely used
What is the Total Length field in the IP header?
It specifies the total size of the packet in bytes
What is the Identification field used for?
To group fragments of the same packet together