[X4U] Making my public folder availble

[Daly Jessup]

Cheryl wrote:

>I have a program I want to allow a couple of friends to get from my 
>computer. I have several questions about this.
>
>1. Since I am using an airport extreme with a wireless network, I 
>assume I have to set up port forwarding. Is this correct?

Yes.

>2. I did set up a port forwarding scheme that works. However, I have 
>a question about port numbers. Is the public port number one you 
>make up and is the private port number one dependent on the protocol 
>being used? If so, how do I determine what to use for the private 
>port number? I know from my linux experience that 22 is the usual 
>port for ssh but I don't know anything about port numbers with the 
>Mac other than this.

I don't know about making up a port number of your own, but if you 
want to, I think you would "make up" the one on your own computer, 
because almost certainly, anyone using an ftp client to reach your 
computer would be sending their request on port 21. Here is a list of 
common ports:
<http://www2.opendoor.com/doorstop/ports.html>

I think if you were going to set up your computer as an ftp server, 
you would just forward traffic on port 21 from outside to port 21 on 
your computer.

>Also, the instructions I read indicated that when I set up the port 
>mapping in Airport Utility I'd choose a service but I don't see any 
>opportunity to do this. I do have file sharing on in system 
>preferences > sharing.

You would set up your computer to be an ftp server, at least in OS X 
10.4 (I don't know about Leopard) in System Prefs/Sharing, then under 
the Services tab, put a checkmark next to "FTP Access". Your visitors 
would need to know your user name and password.

You would set up port forwarding in the Airport Utility. Open up the 
utility, and select your Airport Extreme on the left. Click the 
"Manual Setup button.  Wait while it reads your Airport Extreme 
configuration. Click the Advanced button at the top of the new 
window.  In the Advanced pane, click the Port Mapping tab. Then click 
the little "Plus mark" (+) at the bottom of the list of allowed 
services. In the window that opens, notice the menu labeled 
"Service:" at the top. Choose the FTP Access service. It will be set 
up for forwarding port 21 Public to port 21 Private.  Enter  your 
computer's private IP address.

You can find  the private IP address in the Network System Pref Pane 
by having it "Show" your Airport setup, then looking in the TCP/IP 
tab.  It is given next to "IP Address".

>3. I could put the programs I want to share in my Public folder. 
>However, I have discontinued .mac/mobileme so I'm assuming that I 
>can no longer have people access my public folder by finder > go > 
>idisk > other user's public folder. Am I correct in this assumption 
>and if so can this be done by goto server or is that still only for 
>peopole within the network?

You have to subscribe to MobileMe to have the iDisk.

>6. I also thought of allowing ftp downloads though I realize 
>information isn't encrypted. If I went this route, how would I 
>control what folders people are allowed to access? Is this taken 
>care of in the sharing options or do I have to do more than this?

It seems to me, though I have never tried it, that you could create a 
separate account on your computer for this purpose. Enable "Fast User 
Switching" in the Network Pref Pane so you could have both your 
account and the new "guest" account active at the same time. My guess 
is that if you put your files into the Shared folder in Hard 
Drive/Users/ then gave your visitors the login name and password for 
the new account, then they could FTP to your computer and give the 
username and password for the guest account, and then they could 
retrieve the files from the Shared folder, without knowing your own 
username and password, and without being able to see your private 
documents. Of course, they would still be able to see everything in 
the Hard Drive/Applications/ folder, though.

>5. Miscelaneous: Any other information on safely having people copy 
>or download from my computer--but obviously only what i want copied 
>or downloaded!!!--would be appreciated.

One way I have done this in the past, using my own domain, is to set 
up a sub account at the domain admin page and let people ftp to the 
sub account, where I would  put files for them to download.

Or you could use a  program like FileChute or Pando to just email the 
big files to them.  Or here's one of quite a number of internet 
services for sharing files:  <http://www.box.net/>

If you decide to create a new account on your computer and give its 
login information to others, I'd be interested in hearing if it works 
for you.

Daly
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