IPTABLES help

jludwig wralphie at comcast.net
Thu Dec 22 01:13:06 UTC 2005


On Wednesday 21 December 2005 19:25, Dan de Haan wrote:
> I am trying to write some IPTABLES rules.  These should be simple, but
> arent working for me.  What I want to do is this;
>
> The system has two ethernet adapters eth1 and eth2.  I want it to
> forward TCP traffic on a specific port from devices on eth1 to a server
> on eth0.  It has a dhcp client on eth0 and dhcp serve on eth1.  It must
> drop evertthing but ping and the packets I need forwarded.
>
> Can aynone give me a hint as to were to go?
>
> 	-Dan
If you (as root) run the command
--> iptables -v -n -L 
It will tell you what rules are being used and where the packets are going. 
After that check that forwarding is enabled.
--> cat /proc/sys/net/ipv4/ip_forward
If not;
-->echo 1 >/proc/sys/net/ipv4/ip_forward
And change /etc/sysctl.conf

# Kernel sysctl configuration file for Red Hat Linux
#
# For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and
# sysctl.conf(5) for more details.

# Controls IP packet forwarding
net.ipv4.ip_forward = 1




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