iptables dropping legitimate packets?

[Jan Morales <jan@xxxxxxxxxxx>]

I recently replaced the OS on a PC from RHEL3 to FC3. The iptables 
config file format didn't appear to change, so I used the same file on 
FC3 that I had on RHEL3, reproduced below. The IP address of the PC, 
192.168.0.5, did not change. The PC is on a network that is itself 
behind a firewall that implements NAT and prevents inbound sessions.

Because of this network architecture, the PC under RHEL3 recorded no 
dropped packets, presumably because the network firewall was doing its 
job. However, now that the PC is running FC3 I am seeing dropped packets 
logged. The packets, however, are not inbound sessions. They appear to 
be packets inbound that are part of outbound sessions, e.g. POP and web 
sessions initiated by the PC. The logged packets also don't appear to be 
dropped from every single session, just from some, in a pattern I 
haven't figured out yet. Here is a sample of the logged packets:

Feb 23 23:53:59 toast kernel: iptables: IN=eth0 OUT= 
MAC=00:12:11:a7:86:e2:00:42:17:f4:ed:fa:0a:00 SRC=166.0.230.20 
DST=192.168.0.5 LEN=52 TOS=0x00 PREC=0x00 TTL=105 ID=4731 DF PROTO=TCP 
SPT=80 DPT=33015 WINDOW=64512 RES=0x00 ACK URGP=0
Feb 23 23:56:39 toast kernel: iptables: IN=eth0 OUT= 
MAC=00:12:11:a7:86:e2:00:42:17:f4:ed:fa:0a:00 SRC=66.221.50.162 
DST=192.168.0.5 LEN=40 TOS=0x00 PREC=0x00 TTL=108 ID=822 PROTO=TCP 
SPT=110 DPT=32995 WINDOW=0 RES=0x00 RST URGP=0
Feb 23 23:56:40 toast kernel: iptables: IN=eth0 OUT= 
MAC=00:12:11:a7:86:e2:00:42:17:f4:ed:fa:0a:00 SRC=66.221.50.162 
DST=192.168.0.5 LEN=40 TOS=0x00 PREC=0x00 TTL=108 ID=826 PROTO=TCP 
SPT=110 DPT=32995 WINDOW=0 RES=0x00 RST URGP=0
Feb 23 23:56:40 toast kernel: iptables: IN=eth0 OUT= 
MAC=00:12:11:a7:86:e2:00:42:17:f4:ed:fa:0a:00 SRC=66.221.50.162 
DST=192.168.0.5 LEN=40 TOS=0x00 PREC=0x00 TTL=108 ID=834 PROTO=TCP 
SPT=110 DPT=32995 WINDOW=0 RES=0x00 RST URGP=0

Is there some reason why iptables is dropping, or at least logging, 
these legitimate packets? Is there a difference between iptables in 
RHEL3 and FC3 that accounts for this? My /etc/sysconfig/iptables follows:

# Firewall configuration written by redhat-config-securitylevel
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j 
ACCEPT
-A RH-Firewall-1-INPUT -j LOG -d 192.168.0.5 --log-prefix "iptables: "
-A RH-Firewall-1-INPUT -j DROP
COMMIT

Thanks for any help!
Jan