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 |
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 ♦♦ 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 Harris ♦♦ |
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?