Did not know you ever responded to back in this post previously on the subject.
http://www.linuxquestions.org/questi...at-box-608800/
Plus the same questioned ask multiple times here over the past 3 months.
http://www.linuxquestions.org/questi...tables-607528/
http://www.linuxquestions.org/questi...tables-598536/
http://www.linuxquestions.org/questi...tables-598537/
What might help is explain the goal a bit better. Again I see alot of debian stuff added and you are using a RHEL4 distro. Setup is quite different between the two.
If I understand this you want a simply firewall/gateway router. Letting network traffic bound to the internet on the eth1 side through to the eth0 side to the internet. Then the return data responce from the internet to eth0 through to eth1 back to the orginal lan machine making the request.
Let me know if this is the main first goal. If so the I can provide info on making a simply router under a Redhat type distro.
I would repost the asked info asked in response number 2 from this post I asked to see what changes have taken place since about 2 months ago.
http://www.linuxquestions.org/questi...at-box-608800/
Based on the old responses the ifcfg-eth0 and ifcfg-eth1 you do not define the gateway in eth0 which is the one connected to the internet side. Then you have defined the gateway in eth1 which you say is the lan side. Do not define a gateway on the lan side, just the wan eth0 side.
Take it one step at a time and first get simply masquerading working then you can enable other server options and open ports for them.
Brian