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Okay I've read through various howtos and examples and I think I've got this
configured right, but I'm still experincing a strange problem.  I'm running
RedHat 6.2 with the
2.2.19 Kernel installed.  Masquing works fine in that any internal machines
can see the outside work.  The Linux box can ping the outside work fine as
well.  The other machines can ping the Linux box, but the Linux box cannot
ping the inside machines or itself very well.  If I leave ping going long
enough I seem to get some packets through but with like 85% or more loss.
Whereas if I ping from a windows 2k box the Linux box I get no packet loss,
so I don't think its a physical network problem.  I've went through my rules
and it seems okay, anyone have any ideas what I might be overlooking.

Here is my edited start up script (ip addresses changed)

Any thoughts or suggestions will be greatly appreciated.

#!/bin/sh
#
#
PATH=/sbin:/bin:/usr/sbin:/usr/bin

# LOAD all required IP MASQ Modules

# Needed to initially load modules

/sbin/depmod -a

# FTP

/sbin/modprobe ip_masq_ftp


# ENABLE IP FORWARDING

echo "1" > /proc/sys/net/ipv4/ip_forward

# Enable auto defragging

echo "1" > /proc/sys/net/ipv4/ip_always_defrag

# Set Variables for firewall rules

# External IP Address
extip="192.168.10.1"  ### THIS IS CHANGED IT IS REALLY A REAL IP ADDRESS

# External Interface Name
extint="eth0"

# Internal IP Network
intnet="192.168.1.0/24"
intint="eth1"


# MASQ Timeouts
# 2 hours for tcp sessions
# 10 sec for traffic after the tcp/ip FIN packet is recieved
# 60 sec for UDP traffic

ipchains -M -S 7200 10 60

#### BEGIN FIREWALL RULES ####

# First flush and set default to deny

ipchains -F input
ipchains -P input REJECT
echo "Input Rules\n"
# local interface local machine going anywhere is valid
ipchains -A input -i $intint -s $intnet -d 0.0.0.0/0 -j ACCEPT

# remote interface claiming to be local machines IP spoofing get lost
ipchains -A input -i $extint -s $intnet -d 0.0.0.0/0 -l -j REJECT

# remote interface, any source going to external ip is valid
ipchains -A input -i $extint -s 0.0.0.0/0 -d $extip/32 -j ACCEPT

# loopback interface is valid
ipchains -A input -i lo -s 0.0.0.0/0 -d 0.0.0.0/0 -j ACCEPT

# catch all rule all other incoming is denied and logged

ipchains -A input -s 0.0.0.0/0 -d 0.0.0.0/0 -l -j REJECT

# Outgoing flush and set default
ipchains -F output
ipchains -P output REJECT
echo "output\n"
# local interface any source going to local net is valid

ipchains -A output -i $intint -s 0.0.0.0/0 -d $intnet -j ACCEPT

# outgoing to local net on remote interface, stuffed routing deny
ipchains -A output -i $extint -s 0.0.0.0/0 -d $intnet -l -j REJECT

# outgoing from local net on remote interface stuffed masq deny
ipchains -A output -i $extint -s $intnet -d 0.0.0.0/0 -l -j REJECT

# anything else outgoing on remote interface is valid
ipchains -A output -i $extint -s $extip/32 -d 0.0.0.0/0 -j ACCEPT

# loopback interface is valid
ipchains -A output -i lo -s 0.0.0.0/0 -d 0.0.0.0/0 -j ACCEPT

# catch all rule all other is denied and logged
ipchains -A output -s 0.0.0.0/0 -d 0.0.0.0/0 -l -j REJECT
echo "Forwarding\n"
## Forwarding flush and set default policy of deny
ipchains -F forward
ipchains -P forward DENY

#
#
ipchains -A forward -s $intnet -d $intnet -j ACCEPT
ipchains -A forward -i $extint -s $intnet -d 0.0.0.0/0 -j MASQ


# catch all rule all other forwarding is denied and logged.
ipchains -A forward -s 0.0.0.0/0 -d 0.0.0.0/0 -l -j REJECT
echo "All Done"

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