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for some traces DHCP discovery packets, DHCP option 60 VCI value is EMPTY but in hex area we can see values in Bytes and HEX ... with length 7

Why VCI area is shown empty???


Option 60 length 7 Vendor Class identifier= "empty"

in bytes option code = 3c length = 07 value = 00 00 22 03 48 47 57

asked 05 Mar '15, 05:20

Junaid's gravatar image

Junaid
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What is your OS and which version and what is your Wireshark version? Can you share a capture in a publicly accessible spot, e.g. CloudShark?

(05 Mar '15, 08:21) Jaap ♦

Maybe because the actual value begins with zeroes, which could indicate a string terminator - so the Wireshark dissector probably thinks that the string is finished at the first byte. I'm just guessing though.

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answered 05 Mar '15, 05:49

Jasper's gravatar image

Jasper ♦♦
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may be, issue is actually; my BRAS is also no relaying this to DHCP Is it possible, BRAS is considering it a NULL value also and dropping the packet!??

(05 Mar '15, 06:25) Junaid

RFC 2132 just says the value is a "string of n octets"; it doesn't say "character string", as it does for some other options. The Wireshark dissector currently treats it as a character string; you might need to check with the supplier of whatever hardware/software is sending that packet to find out how that field is to be interpreted.

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answered 05 Mar '15, 17:48

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Guy Harris ♦♦
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question asked: 05 Mar '15, 05:20

question was seen: 2,381 times

last updated: 05 Mar '15, 17:48

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