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Author Topic: Last four bytes of inv messages  (Read 595 times)
TT
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November 17, 2011, 12:26:47 PM
 #1

I've been running a packet sniffer and noticing that many of the inv messages contain four additional bytes at the end that don't seem to be mentioned in https://en.bitcoin.it/wiki/Protocol_specification#inv at all.

What gives? I'm writing a bitcoin node, and when I send an inv message as is specified in that document, I get no getdata messages in reply. So what are these mysterious last four bytes?
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November 17, 2011, 12:40:22 PM
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I'll give a couple examples I just sniffed off my network:

f9 be b4 d9                                      <---- magic bytes
69 6e 76 00 00 00 00 00 00 00 00 00    <----- inv command
25 00 00 00                                      <----- payload length
94 39 95 3d                                      <----- payload checksum
01                                                   <----- inventory count
01 00 00 00                                       <------ MSG_TX
e6 e2 31 d1 65 84 69 dc f1 ec 25 cf 82 a9 76 19 7b a1 cf 44 e1 ae 5f 9a b9 2a d5 a2 32 b6 1b 85  <---- tx hash
9d 79 e5 cd     <------ WTF ARE THESE ?!?!?!?!


f9 be b4 d9                                      <---- magic bytes
69 6e 76 00 00 00 00 00 00 00 00 00    <----- inv command
25 00 00 00                                      <----- payload length
94 39 95 3d                                      <----- payload checksum
01                                                   <----- inventory count
01 00 00 00                                       <------ MSG_TX
e6 e2 31 d1 65 84 69 dc f1 ec 25 cf 82 a9 76 19 7b a1 cf 44 e1 ae 5f 9a b9 2a d5 a2 32 b6 1b 85  <-same tx hash
b2 10 4c 66    <------ AGAIN, WTF ARE THESE ?!?!?!?!

f9 be b4 d9                                      <---- magic bytes
69 6e 76 00 00 00 00 00 00 00 00 00    <----- inv command
25 00 00 00                                      <----- payload length
2b a0 0e 5a                                     <----- payload checksum
01                                                   <----- inventory count
01 00 00 00                                       <------ MSG_TX
81 7f 2f fe dd 0e 83 6e 77 fc 8b 75 4b 74 63 da be 35 c2 8a e2 c1 ec d6 2a 72 ab f6 68 f0 c0 a5  <- tx hash
5e 7f ad 95    <------ huh?!

I'm sure there must be a simple explanation for them.
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November 17, 2011, 08:17:35 PM
 #3

Those aren't covered in the checksum. Did a client accept these messages?

1NXYoJ5xU91Jp83XfVMHwwTUyZFK64BoAD
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