This is a static archive of our old Q&A Site. Please post any new questions and answers at

goosePDU wireshark capture


Hello, I'm trying to build a GooseAPDU Packet with Scapy (Python Framework), and I don't know exactly what is this CONTEXT and UNIVERSAL Class. Has anyone build a Goose Packet in any programming language? This is the error: BER Error: Wrong field in SEQUENCE expected class:CONTEXT(2) tag:0 but found class:UNIVERSAL(0) tag:17


This question is marked "community wiki".

asked 17 Nov '15, 08:12

daydreamingirl_'s gravatar image

accept rate: 0%

Are you 100% sure that this is a Wireshark-related question?

Are you 100% sure that the data you feed to the BER encoder conform to the ASN.1 description of the GOOSE PDU?

Here you can find the meaning of the "class" in Type Identifier octet. It suggests that where you would use UNIVERSAL at higher levels, you need to use CONTEXT-SPECIFIC inside a SEQUENCE. Now the question is whether you specify the Type Identifier Octet "manually" or whether scapy does that for you (improperly in this case).

(17 Nov '15, 09:42) sindy