Attacking the foundation Flashcards
Is IPv4/6 a connectionless protocol?
Designed a a layer 3 connectionless protocol. It makes no effort to validate whether the source IP came from the source.
IPv4 Header - how many fields?
10
How many bytes is the IPv4 Header
Minimum 20 (no data), max is 60 bytes.
Version
4 bit field. Identifies the version of IP.
What is the length field?
A 4 bit field containing the length of the IP header in 32-bit increments. Min value is 5, and max is 15.
What is the differentiated services field?
Formerly, ToS - 8 bit field used to determine priority of each packet.
How many bits in a byte
8
Total Length
Specifies the length of the IP packet including he IP header and user data. Max size is 65,535 bytes
Identification, Flag and Fragment Offset
Fragment and reassemble packets.
TTL
8-bit value used to limit the lifetime of a packet.
Protocol
8 bit
Identifies next level protocol
Header Checksum
Used to determine if any errors have been introduced during transmission
Source IP
32 bit binary value
Destination IP
32 bit binary value
Options and Padding
Break
IPv6
How many fields
8 fields
Version
4 bit - identifies iPv6
Traffic Class
8 bit is equivalent to the IPv4 DS field (Differentiated Services)
Flow Label
20 bit suggests that all packets with the same flow label receive the same type of handling.
Payload Length
16 bit indicates the length of the data portion.
Next Header
8 bit field
indicates the data payload type that the packet is carrying. ICMP as an ex.
Hop Limit
8 bit, IPv6 TTL (IPv4)
Source IPv6
128 bit
