01-06-2004, 03:28 PM | #1 (permalink) |
Junkie
Location: RI
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802.3 Frame Decoding
So, my teacher today gave our class an assignment to capture a ARP packet, then manually decode it. He told us to search the net for a form to decode it. I searched through one of my important classes for a stupid form but could not find a damn thing. I dunno if I'm not lookin in the right place, but does anyone know where I can get one? Thanks.
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01-06-2004, 06:30 PM | #2 (permalink) |
WARNING: FLAMMABLE
Location: Ask Acetylene
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http://www.inetdaemon.com/tutorials/lan/arp.html
Code:
TRANSMISSION LAYER for 802.x protocols 1 2 3 3 4 0 7 5 3 1 9 7 +------------------------------------------------+ | Destination MAC Address | +------------------------------------------------+ | Source MAC Address | +---------------+--------------------------------+ | Protocol Type | +-------+-------+ ARP PACKET 1 2 3 3 4 DATA 0 7 5 3 1 9 7 +---------------+---------------+----------------+ | HRD | PRO | HLN | PLN | +---------------+---------------+----------------+ | OP | SHA ... +------------------------------------------------+ | SPA ... +------------------------------------------------+ | THA ... +------------------------------------------------+ | TPA ... +------------------------------------------------+ | SHA ... Ethernet transmission layer (not necessarily accessible to the user): DESTINATION 48.bit: Destination Address SOURCE 48.bit: Source Address PROTOCOL TYPE 16.bit: Protocol type (set to ARP). Ethernet packet data: HRD 16.bit: Hardware address space (e.g., Ethernet, Packet Radio Net.) PRO 16.bit: Protocol address space. For Ethernet hardware, this is from the set of type fields ether_typ$. HLN 8.bit: Hardware Address Length (0-255 Bytes) PLN 8.bit: Protocol Address Length (0-255 Bytes) OP 16.bit: Opcode: either request or reply SHA nbytes: Sender Hardware Address (this packet), n from the HLN field. SPA mbytes: Sender Protocol Address (this packet), m from the PLN field. THA nbytes: Target Hardware Address (this packet), (if known). TPA mbytes: Target Protocol Address
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"It better be funny" Last edited by kel; 01-06-2004 at 06:35 PM.. |
01-06-2004, 06:31 PM | #3 (permalink) |
I am Winter Born
Location: Alexandria, VA
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www.ethereal.com has a lot of information on packet decoding.
It also has (I believe) the struct definitions for ARP packets (look under the randpkt section, they detail exactly how to create random packets that conform to whatever struct you pass them). Sounds like an interesting project, though.
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Eat antimatter, Posleen-boy! |
Tags |
8023, decoding, frame |
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