What do you mean with disabled?
- no iptables package installed?
- not enabled during building the kernel


the first will be easy to fix I think, the second is a bit harder
or do you mean something else?

1 members found this post helpful.

Thanks for you, but i don't mean that iptables is not installed, it is installed but not enabled or it is disabled for some reasons related to my VOIP Services.
I mean :
so, it is not used yet
also selinux is disabled...

ok if the iptables command works you can try this command


put a ping on a customer machine

for example

$ for ((;) ; do sleep 2; ping -c 3 -w 2 8.8.8.8;done

this will keep it running

check with 'tcpdump' on the server
# tcpdump -i eth0 icmp

# iptables -t nat -A POSTROUTING -s 10.10.10.0/24 --d ! 10.10.10.0/24 o eth0 -j MASQUERADE

then try again the tcpdump command from above


do you see any difference, if the iptables command shows the stuff from before then it is fine. That service is probably just configuring iptables. I don't remember but i think there as some wrapper scripts on redhat that will also exist on centos.

but first try to get it working before trying to make it persistent

does the ping work after the iptables line above (the part after the # symbol that I put there to show it needs to be executed as root.

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Thanks a lot
but i need to say it works when i add the rule for natting by:
and the command for iptables status is:
but after some time it stops again and the output for the same command is: returns as:
Thanks in advance ...

so it works but is not persistent?

I found this page:
http://www.cyberciti.biz/faq/rhel-fe...tion-tutorial/

it contains:this command that can solve the problem:

# /sbin/service iptables save

1 members found this post helpful.

Really Thanks for all, the problem is solved and all is OK now...