TCP Free-BSD setup behaviour.

[saravana perumal]

 Hi ,
 
  Have some behaviour change  with FREEBSD  compared to  LINUX .

1. When sending the Same  TCP packet once again [ Retranmission of TCP packet ] Whether the Same Identification field [ IP packet]used or not .
but when seeing that thru packet capture, Free BSD sending the differnt one [ increases sequentially IP Identification]

2.Retranmission Time is not increasing Linearly with Respect to BSD. not keeping more time interval . AS per RFC 
expecting Retransmission timeout should  increase Linearly. Issue is not seen with Linux Setup

3. Active SYN open state in FREE BSD setup , Does not reach Syn-received State. When Sending syn packet to DUT but  for that FreeBSD is not sending back 
SYN/ACK .  Issue is with Free BSD Setup.Linux works fine,
 
4.When checking the State - TIME-WAIT 
  Sending FIN and expecting the ACK ;Getting the ACK properly.
  Sending Data Segment and Expecting the RST signal not getting the RST ; Instead DUT is sending the Last TCP packet.
 
Issue seen only in Free BSD.
 
Same issue in FIN-WAIT2  & FIN-WAIT1 State also .
  Sending FIN and Expect the ACK : Getting the ACK
  Sending Data segment with Data : Expecting the RST signal from DUT ; but got Last transmitted TCP packet[ FIN -ACK]
 
Any idea about the above scenario would be helpful
 
Thanks,
Saravanan.