Re: what uniquely identifies a TCP/IP packet?

["David Chang" <dchang () fsautomation com>]

Hi,

I'm running into a problem using libpcap for Windows where it sees the same packet twice when my PC is the sender, 
however only once (which is normal) when my PC is the receiver.  This may be due to the software VPN I'm running on my 
PC.  I'd like to remedy this problem by simply dropping the duplicate packets in my callback routine.

My question is: what is the MINIMUM set of attributes in the packet header can uniquely identify a TCP packet?

My first guess is:  ip->ip_src, ip->ip_dst, tcp->th_sport, tcp->th_dport, ip->ip_id, tcp->th_seq, tcp->th_ack, 
tcp->th_flags, tcp->th_win

Can anyone confirm or suggest an alternate list of attributes?

DC