Hi, Im new to iptables, but I wish to configure our firewall running redhat
linux iptables to forward as follow:
- forward traffic port 25 ip source from 123.123.123.123 to a server
internally;
- forward traffic port 25 ip source not from 123.123.123.123 to a server
externally;
is it possible to achieve the above, anyone can give a code or two
many thanks in advance

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Jemy wrote:
> Hi, Im new to iptables, but I wish to configure our firewall running redha
t
> linux iptables to forward as follow:
> - forward traffic port 25 ip source from 123.123.123.123 to a server
> internally;
> - forward traffic port 25 ip source not from 123.123.123.123 to a server
> externally;
> is it possible to achieve the above, anyone can give a code or two
> many thanks in advance

For RH and Fedora, edit /etc/sysconfig/iptables to include something
like the following.  Watch out for line wraps.

*nat
:PREROUTING  ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
:OUTPUT      ACCEPT [0:0]
-A PREROUTING -s 123.123.123.123 -p tcp -m tcp --dport 25 \
-j DNAT --to <"internal" ip addr>
-A PREROUTING                    -p tcp -m tcp --dport 25 \
-j DNAT --to <"external" ip addr>
COMMIT

Don't forget to ACCEPT the traffic in the FORWARD chain, too.

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Thanks Allen, that does the job.. brilliant =)

"Jemy" <cutejemy@REMOVEhotmail.com> wrote in message
news:40f34926@news.starhub.net.sg...
> Hi, Im new to iptables, but I wish to configure our firewall running
> redhat linux iptables to forward as follow:
> - forward traffic port 25 ip source from 123.123.123.123 to a server
> internally;
> - forward traffic port 25 ip source not from 123.123.123.123 to a server
> externally;
> is it possible to achieve the above, anyone can give a code or two
> many thanks in advance
>

[ Post a follow-up to this message ]

On Tue, 13 Jul 2004 10:31:22 +0800, Jemy wrote:

> Hi, Im new to iptables, but I wish to configure our firewall running redha
t
> linux iptables to forward as follow:
> - forward traffic port 25 ip source from 123.123.123.123 to a server
> internally;
> - forward traffic port 25 ip source not from 123.123.123.123 to a server
> externally;
> is it possible to achieve the above, anyone can give a code or two
> many thanks in advance


Nice easy firewall tool for iptables.


http://firestarter.sourceforge.net/

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