IPCHAINS ... again

Hej !

I know that this kind of problem is current. I've follow multiple
documents for setup my network and resolve my problem, and this not
work.
I've used ipchains-howto and ip-masquerade-howto with no success ...

My configuration :

+ Firewall pc connected to ADSL 1Mo
PIII 600 with RAM 500M
2 ethernet cards
Linux Mandrake 2.2.19
ipchains 1.3.10
kernel seems to be well configured for masquerade

+ Four pc running W2K

I can access internet by using squid, but when I kill it and attempt
to connect with a pc in the internal network, this failed. Of course,
I change ip configuration on the client like said in the
IP-MASQUERADE-HOWTO.

Can someone tell me if my configuration script is good ?

Thanks a lot for answers,

RaFFe/

this is my ipchains config script :

#____________________________________
#!/bin/sh
#

MYHOST="a.b.c.d"
PARTNERHOST="e.f.g.h"

ipchains -F input
ipchains -F forward
ipchains -F output

# INPUT
#____________________________________
# Block all packet on all interface
ipchains -P input DENY

# Accept all input from the local network
ipchains -A input -j ACCEPT -i eth0

# Accept input packet from my partner
ipchains -A input -j ACCEPT -i ppp0 -d $MYHOST/32 -s
$PARTNERHOST/32

ipchains -A input -j ACCEPT -i ppp0 -d $MYHOST/32 -p tcp ! -y

ipchains -A input -j ACCEPT -i ppp0 -p ! tcp

# Accept packet if the source is the local network and destination is
the internet
ipchains -A input -j ACCEPT -i ppp0 -d $MYHOST/32 -s
192.168.2.1/255.255.255.0 -p tcp

#
ipchains -A input -j ACCEPT -i lo

# FORWARD
#____________________________________
ipchains -P forward DENY
# Accept outgoing packet for smtp/pop usage - use masquerade
ipchains -A forward -j MASQ -p tcp -s 192.168.2.0/24 -d 0.0.0.0/0 25
ipchains -A forward -j MASQ -p tcp -s 192.168.2.0/24 -d 0.0.0.0/0 110


# use global masquerade for internet connection
ipchains -A forward -j MASQ -s 192.168.2.0/24 -d 0.0.0.0/24 -i ppp0

# OUTPUT
#____________________________________
ipchains -P output ACCEPT

# Active ip firewalling
echo "1" > /proc/sys/net/ipv4/ip_forward