FTP problem, please assist...

[scornflake]

Hello everyone...here's a fun one...
I'm running a small network connected to the outside world via cable modem. all traffic passes through a linksys firewall/router. I'm currently running an ftp site on machine 1.3, using port 21. I have opened ports 20 and 21 and forwarded them to machine ip 1.3. everything's fine up ro here..site works fine.
I would now like to setup another FTP stie on andifferent machine, 1.6. I can set the ftp server on 1.6 to use an alternate port (88, for example), and forward requests on 88 in the router to 1.6. that seems fine internally, but no one outside my network can get to it. is this a problem with the fact that I have port 20 forwarded to machine 1.3? how should I be properly setting this up so one FTP runs on 21, and the other on 88 and they are both accessable from the outside world? I would really appreciate any input...
Thanks
andrew@scornflake.com

 

[ChrisAC]

When FTP traffic arrives at the router, how does the router know which port forwarding rule to use?

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[scornflake]

I should have specified, the traffic for the second FTP server (that traffic which should be going to 1.6) is on port 88. the clients attemppting to connect to this second ftp have configured their ftp clients to use port 88 when connecting to this particular FTP server

 

[roadrun777]

And on 1.6 machine is the FTP server set to run on port 88 also? or is it port 20/21

 

[scornflake]

Yes the FTP server on machine ip 1.6 is set to listen on port 88. Also, I have since discovered that like ftp servers on port 21 where you have to open ports 20 and 21 on a router, the system is whichever port you choose to have the FTP server running on, you need to open that port as well as the one below it (for port 88, open 87 and 88)

This all figured out, however, clients who are trying to connect are somehow, for some reason, sending passive mode requests to the FTP, when the client is NOT set to attempt to use passive mode. The FTP server has been tried both using passive mode(although I'm not sure I know which ports to open for passive mode) and without passive mode. either way, clients set to attempt to connect without passive mode still try to use it, and timeout and get disconnected.

This is really weird...and I hope that was clear enough so that I might get some help.
Thanks,

 

[roadrun777]

Okay, open all outbound port higher than port 1024.
Thats just outbound btw.
Change your FTP servers port to something higher than 1024.
For example, port 3000. You must enable inbound connections on port 3000 (and port forward it to your ftp server which also has port 3000. That should take care of your problems.

Using ports lower than 1024 can be risky, and you should probably not do it for internet accessible ftp servers.