Ports have to be open?
 

Hi!

I want to set up a ftp server. it is allready working fine, but I had to open the port 21. (Ususal for ftp). No I ask myself, if this is not secure? I have 2 port scans a day. So anybody can enter my network? Is there a possibility, wehrer I needn" t open some ports? I hate open ports. I allredy tried alternate ports but they don"n t work.

Thanks for any answer!

sincerely yours

Hi Daiba. Welcome to LinuxQuestions.

If you want to run a server (like ftp), then you must open a port in your firewall for it. Otherwise, a client from the outside can't communicate with it.

One alternative (but that's not a perfect solution either) is to use a non-standard port for the ftp server. Then, it's not obvious for a hacker that it's an ftp server on the other end. You would then have to tell your friends to connect to the server using an address like:
ftp://mycomputer.myisp.domain:15713

Make sure that your ftp server software is up to date and that it hasn't any known security flaws.

Regards
Martin

You definitely have to have an open port in order to run a service such as FTP. But you certainly don't have to broadcast that it is open. Doing a port scan on my machine doesn't turn up anything, but if you try and connect with the ssh protocol on port 23 you will get a response.

Anyway, if you are really worried about security FTP is not the best method of transferring files, you can use sftp/scp protocol over the SSH port if you have sshd running. This will give you an SSL encrypted connection. Free clients like pscp and putty for windows will then let you connect to your machine and transfer files or get a console to play with.

Ports
 

Hi and thanks for your fast respond!

Well I understood, that I must open ports to let it run. But is this not a big lack of security? How do those big companys handle this - if they have a ftp platform.

So which programm is recommended for this ssh? (also for windows?)
And how did you made your port invisible? I have a hardware firewall.

Sorry for those many questions, i hope i am not getting on your nerves!

Greetings!