Non-Standard FTP Port?

Discussion in 'HyperWRT Firmware' started by GhaladReam, Jul 11, 2006.

  1. GhaladReam

    GhaladReam Network Guru Member

    Hi all,

    I have a question. Now, It's quite possible someone posted the answer to this elsewhere, but I couldn't find it.

    I'm using Thibor15c. Up until today, I ran a private FTP server on port 21. Naturally, I had port 21 forwarded to my FTP Server Box. This worked great. Today, I wanted to change that port to something a little less used. My list of banned IP addresses has grown to such an unbelievable size because of anonymous users trying to connect, because I have it set that if you try and connect 3 times unsuccessfully, your IP is banned. No unauthorized person has actually gotten into my FTP, but I don't want to take that chance.

    My thought is that if I take my FTP server off port 21, that will relieve some of the problem. I changed my forwarded port from 21 to something way up there. After doing this, people can connect to my server, but can't see a directory listing, nor can they download files. Does Thibor15c have a built-in scheme of some kind that automatically forwards the FTP data port only when the control port is 21?

    To fix this problem, I set up a port redirection to an internal of 21 and an external of the high port number I want, then removed the old forward mapping to 21. I found that this worked. My second question is, is this as secure? My final question, is how do I ACTUALLY forward the port I want, so it works, instead of having to redirect port 21 to an external port. Note: My FTP server software can be assigned any port, which is what I'd like to use. If there's no other easy way, I'll continue with port redirection.

  2. swinn

    swinn Network Guru Member

    With active FTP the client determines the data port. The Linksys router will only support active FTP if you use the command port 21 and the data connection port 20 (the default FTP ports).

    You need to look into configuring passive FTP mode with your FTP server. With passive you will configure your FTP server what data ports to use (so the server tells the client what port to use).

    So as an example for passive mode, setup your FTP server to use port 5000 for the command port and passive ports 13000-13050. Then in your router you want to forward ports 5000 and 13000-13050 to the IP of your FTP server. Then on your FTP client you use, set it to use passive mode.
  3. Esquire

    Esquire Mesquire Staff Member Member

  4. lol24h

    lol24h Network Guru Member

    Hey man, I'd like to thank you for your post. I've just thinking, why it doesn't worked. And also very helpful was the next one, information ( helped me understand how it all works. THX !!!
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