HELP----Qmail clustering

["hewt" <hewt@xxxxxxxxxx>]

    I encountered a problem and need your help now.

I want to balance the load of qmail using LVS,
now I can send mail to outside while cannot receive mail
from outside, I opened 25 port on the director machine,

I have already turned off identd on realserver and director,
while when I send mail from outside to the cluster,
ipvsadm -ln still shows:

Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port          Forward Weight ActiveConn InActConn
TCP  172.16.100.1:25 wlc persistent 360
  -> 192.168.6.3:25              Masq    1      0          1

I cannot understand why the connection is InActConn?

and I use tcpdump on the realserver(192.168.6.3):

[root@test2 /root]# tcpdump -ln 'port 25'
Kernel filter, protocol ALL, datagram packet socket
tcpdump: listening on all devices
15:35:02.585515 eth0 < 202.99.43.142.1978 > 192.168.6.3.smtp: S
1414027921:1414)
15:35:02.585559 eth0 > 192.168.6.3.smtp > 202.99.43.142.1978: R 0:0(0) ack
14140
15:35:30.693664 eth0 < 202.99.43.142.1997 > 192.168.6.3.smtp: S
1435933161:1435)
15:35:30.693706 eth0 > 192.168.6.3.smtp > 202.99.43.142.1997: R 0:0(0) ack
14350