TPROXY doesn't properly close connections in Linux 2.6.39

[Brian G <bgunlogson5@comcast.net>]

I've been using TPROXY for a transparent HTTP proxy. I've noticed that 
it is not closing the connection when the other side does.

The module is marked EXPERIMENTAL in Linux kernel 2.6.39. What is the 
oldest version of the Kernel that TPROXY is not marked EXPERIMENTAL, so 
I can upgrade to that Kernel? Or is TPROXY still marked EXPERIMENTAL in 
the latest kernels?

Why is TPROXY marked as EXPERIMENTAL? Are there any known bugs in 2.6.39?

Here is the firewall script I am using to setup TPROXY:

ip -f inet rule add fwmark 1 lookup 100
ip -f inet route add local default dev eth0 table 100
echo 0 > /proc/sys/net/ipv4/conf/eth0/rp_filter

iptables -t mangle -N DIVERT
iptables -t mangle -A DIVERT -j MARK --set-mark 1
iptables -t mangle -A DIVERT -j ACCEPT

iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT

iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY 
--tproxy-mark 0x1/0x1 --on-port 12380