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대문 / 네트웍, 프로그래밍 / ICMP(Internet Control Message Protocol)

ICMP(Internet Control Message Protocol)

1.1. 개요

IPv6 Fundamentals: A Brief Look at ICMPv6 Neighbor Discovery
참고 영상

  • ICMP는 다음과 같이 IP datagram 과 함께 구성된 모습을 띄고 있다.
    <- IP datagram ->
    IP header ICMP message

  • ICMP message
    0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
    8bit Type 8bit Code 16bit Checksum
    (Type과 Code에 따라서 다른 형식을 갖는 부분)

  • ICMP message Type and Code (참고: [http]http://www.iana.org/assignments/icmp-parameters[])
    Type Code Name Reference
    0 0 Echo Reply (RFC792)
    1 - Unassigned (JBP)
    2 - Unassigned (JBP)
    3 Destination Unreachable (RFC792)
    0 Net Unreachable
    1 Host Unreachable
    2 Protocol Unreachable
    3 Port Unreachable
    4 Fragmentation Needed and Don't Fragment was Set
    5 Source Route Failed
    6 Destination Network Unknown
    7 Destination Host Unknown
    8 Source Host Isolated
    9 Communication with Destination Network is Administratively Prohibited
    10 Communication with Destination Host is Administratively Prohibited
    11 Destination Network Unreachable for Type of Service
    12 Destination Host Unreachable for Type of Service
    4 0 Source Quench (RFC792)
    5 Redirect (RFC792)
    0 Redirect Datagram for the Network (or subnet)
    1 Redirect Datagram for the Host
    2 Redirect Datagram for the Type of Service and Network
    3 Redirect Datagram for the Type of Service and Host
    6 Alternate Host Address (JBP)
    0 Alternate Address for Host
    7 - Unassigned (JBP)
    8 0 Echo (RFC792)
    9 0 Router Advertisement (RFC1256)
    10 0 Router Selection (RFC1256)
    11 Time Exceeded (RFC792)
    0 Time to Live exceeded in Transit
    1 Fragment Reassembly Time Exceeded
    12 Parameter Problem (RFC792)
    0 Pointer indicates the error
    1 Missing a Required Option
    2 Bad Length
    13 0 Timestamp (RFC792)
    14 0 Timestamp Reply (RFC792)
    15 0 Information Request (RFC792)
    16 0 Information Reply (RFC792)
    17 0 Address Mask Request (RFC950)
    18 0 Address Mask Reply (RFC950)
    19 - Reserved (for Security) (Solo)
    20-29 - Reserved (for Robustness Experiment) (ZSu)
    30 - Traceroute (RFC1393)
    31 - Datagram Conversion Error (RFC1475)
    32 - Mobile Host Redirect (David Johnson)
    33 - IPv6 Where-Are-You (Bill Simpson)
    34 - IPv6 I-Am-Here (Bill Simpson)
    35 - Mobile Registration Request (Bill Simpson)
    36 - Mobile Registration Reply (Bill Simpson)
    37-255 - Reserved (JBP)
    • Type 에 따라서 일부는 Code를 추가적으로 필요하거나 필요하지 않다.

  • ICMP checksum (엄밀히는 Internet checksum 이라고 부르며 Computing the Internet Checksum (RFC1071) 에 그 구현방법이 명시되어 있다.)



  • ICMP echo request and reply
    0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
    8bit Type (8 or 0) 8bit Code 16bit Checksum
    Identifier Sequence number
    Variable data

  • ICMP address mask request and replay
    0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
    8bit Type (17 or 18) 8bit Code 16bit Checksum
    Identifier Sequence number
    32bit subnet mask

  • ICMP timestamp request and replay
    0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
    8bit Type (13 or 14) 8bit Code 16bit Checksum
    Identifier Sequence number
    32bit originate timestamp
    32bit receive timestamp
    32bit transmit timestamp

1.2. 예제소스


1.3. 참고자료


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