Just Kooky

So PCS can pick up the fields just fine, as long as they're zeros. Make SYN *and* ACK set to '1' and everything is FUBAR.

Packet data taken from:
http://support.microsoft.com/kb/172983

Syn Packet Data:
TCP: ....S., len: 4, seq: 8221822-8221825, ack: 0, win: 8192, src: 1037
dst: 139 (NBT Session)

Syn-Ack Packet Data:
TCP: .A..S., len: 4, seq: 1109645-1109648, ack: 8221823, win: 8760,
src: 139 (NBT Session) dst: 1037

>>> from pcs.packets.tcp import tcp
>>> import binascii
>>> synAck = "008B040D0010EE8D007D747F60122238012D0000020405B42020"
>>> syn = "040D008B007D747E0000000060022000F2130000020405B42020"
>>>
>>> synPkt = tcp(binascii.a2b_hex(syn))
>>> synAckPkt = tcp(binascii.a2b_hex(synAck))
>>>
>>> print repr(synPkt)
[TCP: reset: 0, reserved: 0, sequence: 8221822, ack: 0, checksum: 61971, offset: 6, syn: 1, urgent: 0, window: 8192, push: 0, ack_number: 0, dport: 139, sport: 1037, fin: 0, urg_pointer: 0]
>>>
>>> print repr(synAckPkt)
[TCP: reset: 4, reserved: 0, sequence: 1109645, ack: 1, checksum: 301, offset: 6, syn: 9, urgent: 0, window: 8760, push: 2, ack_number: 8221823, dport: 1037, sport: 139, fin: 0, urg_pointer: 0] Read more...