pop-2 scanning

[tdunn () BAYSOFT NET (tdunn () BAYSOFT NET)]

we are recieving pop-2 scans from various sources also.
Initially we saw SYN/FIN packets, then they were followed
by SYN - SYN/FIN packets, sorta link hanging up the phone
before you can answer type of thing, an associate of mine
had a theory that older versions of linux and BSD might
respond to that sequence with FIN/ACK, anyone know if thats
true or not ???