[mbotta]

Setup:
ADSL modem
Airport base station
2 airport-equipped macs sharing the internet connection
A third mac trying to connect remotely over the internet

How do I find out the internet address of each of the two internet sharing macs?

I mean, internally each has a different address - 10.0.0.150 and 10.0.0.151 -, but obviously externally the address remains the original one of the ADSL connection. So, given I know my ADSL-based IP-address, how do I identify the address of each of the sharing macs?

Sorry for the non-technical formulation; this is not my speciality...

Thanks,

mbotta

[John Strung]

In order for the external Mac to connect to one of the Macs behind the Airport base station, you will have to go into the Airport base station setup utility and use the port mapping feature to map the appropriate port to the appropriate Mac.

For instance, if you want the external Mac to be able to connect to the Mac at 10.0.0.150 by Apple File Sharing Protocol (AFP) you would have to forward (map) TCP Port 548 to 10.0.0.150. Then when the external Mac tries to log into the Airport Base Station's external IP address, the request will be forwarded to 10.0.0.150.

Similarly if you turn on Personal Web Sharing on the Mac at 10.0.0.151, you would have to forward TCP Port 80 to 10.0.0.151.

You cannot forward the same port to more than one computer.

[mbotta]

John,

Thanks for your answer.

If I understand correctly, the external mac should then connect over 123.45.67.89:548 or 123.45.67.89:80?

Isn't this done automatically by the base station?

Should I then change the firewall settings to reflect the changed ports? How?

Thanks once again.

mbotta

[John Strung]

>If I understand correctly, the external mac should then connect over 123.45.67.89:548 or 123.45.67.89:80?

You can just use 123.45.67.89 without specifying the port when you log in. Airport will then automatically forward the port as long as port mapping is set up. You don't have to "force the port" by specifying it in the URL.

>Isn't this done automatically by the base station?

Unless you set up port mapping in the Airport Base Station, all ports are blocked to incoming access.

>Should I then change the firewall settings to reflect the changed ports?

What kind of firewall are you running? If you just mean the Airport Base Station, mapping or forwarding the ports automatically opens them.

[mbotta]

I am using the OSX firewall from the sharing panel in the system preferences.

How can you specify the mac you want to reach if you don't force the port?

Thanks,

mbotta

[John Strung]

[QUOTE]Originally posted by mbotta:
[B]I am using the OSX firewall from the sharing panel in the system preferences.

>How can you specify the mac you want to reach if you don't force the port?

You can't for AFP because there is no way that I know of to use AFP on any port other than TCP 548 (unless you are using OS 9 and purchase the commercial version of SharewayIP from http://www.opendoor.com). I don't know of any way to do it under OS X, although there might be such a way.

You might be able to change the port for PWS, but I have never used it.

I simply turn my OS X firewall off. I presume there are ways to open ports in it, perhaps with a third party GUI like Brickhouse.

[mbotta]

Hm, well, no luck My macs aren't accessable from outside, although they are perfectly visible to each other on the airport network.

I have tried a simple port forwarding:

public port 20
private IP address 10.0.1.14
private port 20

as well as

public port 21
private IP address 10.0.1.14
private port 21

All this for the FTP service alone (I looked for the port numbers in OSX's firewall).

Any idea what I may be doing wrong?

Thanks,

mbotta

[John Strung]

That should work as long a .14 is in fact the local address of the FTP server. Check to make sure you have turned off the built-in OS X firewall (in the Sharing preferences panel).

[mbotta]

I tried it both with the firewall on (with an exception for those ports...) and off. They can't get through...

What can I be doing wrong that I am not thinking of.

Yes, .14 is in fact the private address.

Thanks,

mbotta