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DHCP Option 60 - VCI value is EMPTY


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

accept rate: 0%

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 ♦

2 Answers:


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.

answered 05 Mar '15, 05:49

Jasper's gravatar image

Jasper ♦♦
accept rate: 18%

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.

answered 05 Mar '15, 17:48

Guy%20Harris's gravatar image

Guy Harris ♦♦
accept rate: 19%