port redirecting

st3reo · 11-12-2004, 07:44 AM

Hey

I have a red hat box and I have 3 ips on eth0
If you for example try to connect to port 21 if you connect to ip1, ip2 or ip3
they all work so you end up in the same place but I want to set it so that connections to port 21 to be permited only on ip1 and if you try to connect to ip2 or ip3 to deny connection to the port
Hope I`ve been pretty clear,
Can anyone help me?

Thanks a lot,

acid_kewpie · 11-12-2004, 07:50 AM

you can either use a firewalll on all NIC's and openly open the port on the single NIC you want, or more easily you should be to configure your ftp server to only listen on either 1) that interface or 2) the subnet applicable to that NIC.

st3reo · 11-12-2004, 08:01 AM

yeah well I just gave port 21 as an example,

how do I do it for other ports.

PS It only has one NIC

Demonbane · 11-12-2004, 05:35 PM

As acid_kewpie mentioned you can use a firewall, for example:

Code:

/sbin/iptables -P INPUT DROP
/sbin/iptables -A INPUT -p tcp -d <ip1> --dport 21 -j ACCEPT