Fichas
Network Layer Protocol Headers
Fichas del conjunto (85)
- 1What is ARP?Address Resolution Protocol
Meaning..
I have your IP...what is the MAC for this IP? - 2ARP header is variable length but we are concerned with the first ______ Bytes?28
- 3In the ARP Header What are the possible OPCODES in hex and what do they mean?00 01 = request
00 02 = reply
00 03 = RARP - 4For ARP Header what are the 9 fields in order?H/W type; Protocol Type; H/W Size; Protocol type; opcode; SMAC; SIP; TMAC; TIP
- 5What happens after the DORA process?3 gratuitous ARP's
- 6What is the syntax when filtering ARP in wireshark to show all ARP requests?arp.opcode == 1
(1, 2, 3) - 7The following Exploitation methods and vulnerabilities pertain to which header? cache poisoning man-in-the-middle (MITM) exploitsARP
- 8What is the variable length of the IPV4 Header?20 - 60 Bytes
- 9T or F: Total IP Lenth AKA TIPL is the length of the datagram which includes the IPV4 header.True
- 10What is the min - max datagram size....... IPV4 Total IP Lengthmin of 20 Bytes, Max of 65,535
- 11T or F: the Identification field of the IPV4 header aids in assembling fragments of a datagramTrue
- 12What doe the IP Flags represent in the IPV4 Header?Identify whether the datagram can be fragmented and if the receiving host should expect more fragmented packets for this datagram.
- 13What does the Fragment Offset Field do? (13 bits)it indicates where in the datagram this fragment belongs.
- 140 000 =?May
- 150 > 000 =?Last
- 162 000 =?First
- 172 > 000 =?middle
(more coming) - 184 000 = ?Don't
- 198 000 =?reserved
- 20t or F: TTL or Time to live indicates the max # of hops a datagram can make before being discarded. (max TTL 255)True
- 21IPV4 header next protocol field hex value = what ? 01ICMP (layer 3)
- 22IPV4 header next protocol field hex value = what ? 02IGMP
- 23IPV4 header next protocol field hex value = what ? 06TCP
- 24IPV4 header next protocol field hex value = what ? 08EGP
- 25IPV4 header next protocol field hex value = what ? 11UDP
- 26IPV4 header next protocol field hex value = what ? 58IGRP
- 27IPV4 header next protocol field hex value = what ? 59OSPF
- 28When filtering IPV4 header in wireshark, what is the syntax to show all TCP packets?ip.proto == 6
- 29When filtering IPV4 header in wireshark, what is the syntax to show all packets from specified IP Address?ip.src ==
- 30When filtering IPV4 header in wireshark, what is the syntax to show all packets to or from specified IP Address?ip.addr ==
- 31What are the 14 fields in the IPV4 Header in order?version; Header Length; Type of Service TOS; Total IP Length TIPL; Identification; IP Flags; Fragment Offset; TTL time-to-live; Next Protocol; Check Sum; SIP; TIP; Options; Padding
- 3244 1 2 2 3 313 1 1 2 4 4 opt padIPV4 header by the numbers
- 330 000 1 fff =?may Frag
- 342 000 3 ffff = ?More Frag
- 354 000 =?Don't Frag
- 368 000 =?Reserved
- 37What is the fixed size of the IPV6 Header?40 Bytes
- 38How many Bytes does an IPV6 address have?16
- 39What does the IPV6 header use as verbage instead of the TTL field compared to IPV4?Hop Limit
- 40What are the 8 fields in an IPV6 header in order?IP version; Traffic Class; Flow Label; Payload Length; Next Header; Hop Limit; Source Address; Destination Address
- 41ARP by the Numbers = ?2 2 1 1 2 6 4 6 4
- 42IPV4 by the numbers = ?44 1 2 2 313 1 1 2 4 4 options padding
- 43IPV6 by the numbers = ?4820 2 1 1 16 16
- 44In the IPV6 Header, in the next header field, what does 0x3a mean/signify as the next header?ICMPv6
- 45T or F: in IPV6 the payload length does not include the length of the IPV6 header (in contrast to the IPV4 total length)True
- 46In regards to IPV6, What is the calculation to determine the Total IP Length?40 + Payload Length = TIPL
- 47What is the syntax in wireshark to show all IPV6 packets that contain TCP headers?ipv6.nxt == 06
- 48T or F: IP datagrams can be broken down into smaller fragments to allow proper encapsulation of IP traffic within various MTU-sized Data Link Layer Protocols.True
- 49T or F: Fragments are reassembled at the distant host once all fragments are received.True
- 50What are the Steps in regards to Fragmentation to get the Flag Offset (F.0.)?Step 1: Convert TIPL and IPHL to DEC
Step 2: TIPL – IPHL = x [x = payload in Decimal]
Step 3: x / 8 = y [divide the payload by 8]
Step 4: Convert Y (DEC) to HEX
Y = Fragment Offset (F.O) - 51Once you have your Fragment Offset, How do you find out what fragment you are on?Step 1: Flag w/offset – 2000 = x [get the current frag hex number & subtract by the starting Frag]
Step 2: convert x (HEX) to DEC
Step 3: x / F.O. (DEC) = y
Step 4: y +1 = z [ Z being the Fragment you’re on] - 52What are the Steps when asked “what is the next fragment”?Step 1: Solve for the F.O.
Step 2: Current Frag (HEX) + F.O. (HEX) = xxx
Step 3: Answer will be 2 things… last frag and more frag. Example 0 1A4 and 2 1A4 - 53T or F: ICMP provides error reporting, Flow control, and first hop gateway redirection.True
- 54What are the 2 categories of ICMP Messages?Informational and Error
- 55What are the Types we care about in this MOD in the ICMP Header field?0=Echo Reply
3= Destination Unreachable
5=Redirect
8=Echo Request
11=TTL Exceeded - 56RFC states that in an error message, the data portion must contain what?must contain the original (offending) IP header including all options plus at least 8 bytes of additional data.
- 57What are the ICMP type 3 codes we care about in the Code Field?0 = Network Unreachable
1 = Host Unreachable
2 = Protocol Unreachable
3 = Port Unreachable - 58T or F: You will only get a code in the code field of ICMP header if there an error occurs.True
- 59When using Wireshark how do you filter to show all ICMP packets with a destination unreachable/port unreachable error condition?icmp.type == 3 and imcp.code == 3
- 60icmp.type == 8 and ! (icmp.code == 0)FYI for Wireshark
- 61What are the ICMP exploitation Methods and Vulnerabilities?1) DoS Exploits
2) Netmask request for enumeration
3) ICMP redirect exploit for MITM
4) Payload can be used to transmit through firewalls
5 ) Some DDoS attacks such as trinoo
read page 40 - 62T or F: 00 is the default for many ICMP messages, type 3 and its associated codes can be used in enumeration efforts.True
- 63What is used in TCP to maintain order and assure receipt?Sequence #'s and Acknowledge #'s
- 64What are the 11 fields in the TCP Header?SPORT, TPORT, Sequence #, Acknowledge #, Data Offset, Reserved, Control Flags, Window Size (MTU), checksum, Urgent Pointer, Options
- 65What does the Sequence number in the TCP header represent?currents block's position in the overall message.
- 66T or F: The sequence number, when started off, is a random high port.True
- 67What does the Acknowledge Number represent in the TCP Header?the next sequence number expected from the other end.
- 68T or F: the acknowledgement Number is 00 00 00 00 for the syn portion of the 3-way handshake.True
- 69What happens to the seq and ack #'s when looking at a packet in the syn-ack portion of a 3- way handshake?the sequence is set (random) and the ack # is copied from the syn portion of the 3-way handshake and incremented by 1 and then becomes the ack # in the syn-ack packet
- 70T or F: once the session has been established in the TCP connection, the sequence and ack # will vary in increment as determined by the size (payload) of the data being transmitted.True
- 71This field in the TCP Header... represents the number of 32-bit words that are in the TCP Header.Data Offset
- 72In the Control Flags field of the TCP header, what are bit possibilities?C E U A P R S F
University of Alabama Plays really shitty football
Cwr Ecn-echo Urg Ack Psh Rst Syn Fin - 73If on, push data to up the stack as soin as possible for applications such as Telnet or FTPPSH
push bit (8) - 74What TCP header field is being described below? If greater than zero and the urgent flag i set, then this field points to how far into the data stream urgent data extends.Urgent Pointer
- 75T or F: The only time you ever increment the seq# by one is during a 3-Way handshake and a 4-way tear down.True
- 76T or F: There is zero data being transmitted during a 3-Way handshake and 4-way tear downTrue
- 77When looking at packets during a TCP connection, the sequence # always increments by the TCP payload.True
- 78What determines when the seq# and ack # flip during the TCP connection?when the communication changes directions...Meaning look at the TIP and SIP SPORT and TPORT to notice when communication is changing.
- 79What is the steps for calculating the next sequence & ack number in the TCP Header using IPV4?1) TIPL - IPHL - Data Offset = TCP Payload
2) TCP Payload + sequence # = next seq or ack #
3) determine if comm change directions - 80What is the steps for calculating the next sequence & ack number in the TCP Header using IPV6?1) Payload Length - Data Offset = TCP Payload
2) TCP Payload + sequence # = next seq or ack #
3) determine if comm change directions - 81These are referring to which Header? -OS enumeration by ISN -TCP session Hacking -Service enumeration through responding TCP ports - custom flags to bypass ACL'sTCP
Read page 52 for more shit - 82This header /protocol provides for a connection-less unreliable transport mechanism. The upper layers protocols assume the responsibilities of ensuring delivery and accuracyUser Datagram Protocol (UDP) Header
- 83What are the Fields in the UDP Header?SPORT, TPORT, Message Length, checksum
2 2 2 2 - 84T or F: The UDP Message length field in the UDP Header represents the entire UDP header and data length.True
- 85What are the vulnerabilities/exploit methods to the UDP Header?-exploit poor router ACL's
-security left to the upper layer protocols
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- Descripción
- college (Network Layer Protocol Headers) Protocol Analysis Fichas sobre Network Layer Protocol Headers, creado por jeriel.juarbe2031 el 24/09/2014.
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- jeriel.juarbe2031
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