[tor-dev] Understanding Tor and SOCKS

Hi everyone!

I am trying to understand the communication between an application and Tor (especially connecting to a hidden service). I am tracing packets on loopback between a torified netcat request to connect to a .onion address. When the connection gets granted I am getting a response from the socks server: (hex data of the tcp payload)

0x05 0x00 0x00 0x01 0x00 0x00 0x00 0x00 0x00 0x00

Regarding to the SOCKS specification this means that the request is granted. But I don't understand the 0x01 in byte no 4. It means IPv4 address in the SOCKS specification, but the following part of the destination address and port (the following 0x00's) are empty. So what does that 0x01 mean?

Can someone explain me that?

Thank you!

Cheers, spriver