Port Forwarding On Linux to Windows

What i want to do is this....


Set up an ftp server on a windows machine behind the linux box.

I want people to be able to acces this windows ftp server from the internet.

I did the same thing with my home network, but I used FreeBSD (unix variant) instead of RedHat Linux.  Anyway, the concepts are the same.  Generally speaking, what you want to do is called IP masquerading.  This means that you will only have one IP address visible to the outside world (24.x.x.x), and all machines on the internal network (including the FTP server) will be translated by the linux box.  This will make all traffic appear as if it is coming from 24.x.x.x.  So actually, there are two distinct steps involved:

1.  Make sure that your linux box is masquerading IP addresses properly for regular internet traffic (which it sounds like it is.)  In other words, verify that you have internet connectivity on the windows box.  For mucho details on this, check out the IP Masq how to:
http://www.europe.redhat.com/documentation/HOWTO/IP-Masquerade-HOWTO.php3

2.  a.  Allow FTP traffic to the windows ftp server in your firewall commands (if you even have a firewall - I can't really tell from your original post)
    b.  Redirect FTP traffic arriving at 24.x.x.x to 10.0.0.1.
 
For part 2 a., I started out by simply allowing all tcp traffic to the windows box.  This involved a command in my ipfw rules stating:
$fwcmd add allow tcp from any to 10.0.0.1
After you verify connectivity and complete part b., you can come back and tighten this rule to only allow traffic destined for the specific ftp ports (20 and 21).

For part 2 b., I had to put a "redirect_port" command in my NATD rules.  I basically am telling the FreeBSD box to forward all ftp traffic to my windows ftp server, so that machines on the internet 'feel like' they are communicating directly with the ftp server.

Again, my case was for FreeBSD, and that's why you see the examples with IPFW and NATD.  But the concepts behind Linux will be the same; the software packages are just a little different.  The RedHat site is loaded with How-To's and FAQ's on this subject.  I bet you can find the specifics there.

Cheers,
-E

hi,
  ekestes is right on the way u have to proceed.
No u dont need to install ftp server on linux machine.
The work of penguin box here is just to masquerade and
to do forwarding stuff.
ftp server on win machine would suffice.


u can take some idea from the port forwarding question too

best wishes

I'm confused a little about your question. Let's say in this way.

You have a network. Let's assume you have 2 boxes. Machine A contains Linux, 2 network cards (one for internal LAN-> NIC 1, another for external/ ADSL-> NIC2)... Machine B connects to LAN as Machine A's NIC1 does. You can't ping...

Here is my suggestion.
1. You should assign different segment IPs on NIC1 and NIC2 in machine A, such as 192.168.x.x and 10.1.x.x with netmask 255.255.255.0. Because within same IP segment, 2 NICs could NOT forward data.

2. eg. In machine A, NIC1 is 192.168.1.1, NIC2 is 10.1.1.1 - on your second machine you can assign 192.168.1.2 (all netmask is 255.255.255.0). Trust me, if all network cards are configured well, you can ping between 192.168.x.x with 2 machines.

3. When you configure NIC2 connecting to ADSL, you have to install ADSL PPPoE driver for high speed modem. Most PPPoE setup includes the step to configure firewall/ IPMASQ. You should select and enable IPMASQ.

If this didn't work in your situation, let me know. I can help you. I have a workable network sharing internet connection thru ADSL with 4 computers at home. I believe this will work in your network too.

Have fun in Linux.

The Question has been a least partially answered .. I don't know how  simple question gets so misleading ..to recap ---
I have a linux machine at home connected to a cabel modem. I use it as a gateway (MASQ 'ing) .It allows me to conenct another 5 windows machines to the internet with the one IP. With me so far? good. ok now...
the linux machine doesn't have much space
the widows machine does have space.
i want to be able to setup an ftp server on a windows machine BEHIND (obviously) the linux machine (the one box with a real IP address) and I want to be able to connect to the windows machines ftp server fromsomewhere other than my own damn network !! I can ping transfer files hell i can adminsiter the box from anywhere with webmin. This is a Question about PORT FORWARDING. Some of the stuff above is helpful, (Woudl eb more helpful if someone coudl translate the freebsd stuff to linux cmds.

Thanks for your efoorts so far.

Jules, i posted linux commands above... now, you got a cablemodem, so, are you sure your ISP let you put up services? some ISP's firewalls deny incoming connections to their clients in some ports...

garisoain,

they don't exactly encourage it but the services are not denied or blocked.

Yours is the answer I think I am looking for, i just have to recompile the kernel to be sure.. bare with me I will get back too you

thanks all for the help.

Jules™