Port Forwarding And Ip In Airport/router/mac



I have been trying to open all the necessary ports in my Mac/Airport/Router, and just can't get it work.
I am connecting a single computer wirelessly via an Airport Express and a router. to be honest, i am not very good at this and i am not even sure i fully understand what i am doing.

1) to start with, is it correct that i need to open the ports i need in all of them, airport+router+computer?

2) the main problem i think is with the IP addresses. I am not sure what IP addresses i should use. on some helpsite i read that in order to set this up i need to create a static IP address (at the moment i am using the default DHCP option). Is this true? I tied to do it, but then i cannot connect to the internet anymore??
and should i use the same IP addresses for computer/airport/router? the addresses at the moment seem to be very different, eg some are like 86.129.xx.xxx and some are like Do I need to create a set of manual IP addresses?

Please please help me!!
thanks very much


For the Airport Express:
Not provided:
System configuration in explicit detail.
Router's manufacturer and model number.
System / MacOS X version.
application(s) name(s) and version number(s)

Is this your system configuration? ...

---(coax)---'Cable modem'---(Ethernet)---'(unknown) Router'---(Ethernet)---'Airport Express'

Do you realize that in the 'Preferences' of most, if not all applications, is at least a default port number. Thus, that should be enough information to do a basic port forwarding configuration of a router, of which the 'Airport Express' is also.

To answer (1):
Yes, a port or ports may have to be toggled on the router, and most likely with the Airport Express.

To answer (2):
Please, do not fool with anything in 'System Prefernces' 'Network' utility. One should rarely have to visit this utility.


Assuming the system configuration described above is correct.
You need to be able to connect the Mac to the internet.

01. Turn OFF the cable modem, router, and Mac.
02. Connect the Mac directly to the router.
03. Wait ... no more than 40 seconds.
04. Turn ON the cable modem, then the router, then the Mac.
05. Go to 'System Preferences' 'Network'.
06. Select your locatiion via the 'Location:' popup menu item.
07. Select the 'Show:'s 'Built-in Ethernet' popup menu item.
08. Via the 'PPPoE' tab - make sure the 'Connect using PPPoE' check box has no check mark.
09. Via the 'TCP/IP' tab - select the 'Configure IPv4:'s 'Using PHCP' popup menu item.
10. Click on the 'Apply Now' button.
At this point, your router should assign you a local IP address.
Try connecting to the internet. You should be able to. If so, continue ...

You do know that it is best, to first hardwire connect (via an Ethernet cable) the Mac to the router - so as to configure the router (via a web browser) and verify the port forwarding assignment actually works?
Only then disconnect the Mac from the router, and repeat the port forwarding port assignment process with the Airport Express, via Apple's software - I would perform this via an Ethernet connection; and, once the Airport Express was cofigured - connect to it wirelessly.

Each router manufacturer uses a different set of web pages (produced from within the routers built-in server); thus, as with the information - there is no way say how to configure the router for port forwarding.
You should have receive some information, with the router, with respect to configuring it. If not, most router manufacturers provide such manuals as '.pdf' files on their web sites.

'Airport Express' (based on here):
01. Open AirPort Admin Utility, located in Applications/Utilities.
02. Select your base station and click Configure.
03. Enter the base station password if necessary.
04. Click Port Mapping.
05. Click Add and enter the following information:
06. Enter the port number(s).


Ignore the reply from barhar above. That method is to convoluted and not necessary. There is absolutely no need to turn off the modem, it isn't involved in the port forwarding settings at all. There's abolutely no point in connecting the Mac directly to the router either, nor to use a cable to connect the Mac to your base station, no matter what that base station is. You have the network working, so you can connect via Airport. Don't pull out cables or turn anything off!

The only things you need to change are the IP address of your Mac, and the port forwarding settings in your Airport Base Station.

If you use Airport and DHCP, you'll get a dynamic ip. To change that into a static ip, you need only do this: write down the IP address you see in the TCP/IP panel. Then change to "Manual with DHCP" (I'm not sure about the exact wording as I use another language on my computer). Enter the address you wrote down and click on "Apply". You might want to add at least one DNS server to the list, so check the information from your ISP on which servers to use.

Now you need to open all the ports that you want to use in your firewall (if you're using one, check your settings in the Sharing preference pane), and then set up the port forwarding in Airport Admininstrator, so that they are all forwarded to the address you wrote down earlier. Save the settings and restart the Airport base station and test the connection.


Re-connecting the Mac to the internet:
The original post stated 'I cannot connect to the internet anymore'; but, nowhere indicates that the computer used by the poster, to post 'Port Forwarding And Ip In Airport/router/mac', was on the same network. I made no assumptions that he was.

Setting the 'System Preferences' 'Network's 'TCP/IP' tab's 'Configure IPv4:'s popup menu to 'Using PHCP' (of the Mac unable to connect to the internet); then turning OFF the cable modem, router, and Mac; and, then turning them back ON (cable modem first, router second, and Mac third) - are valid ways to re-establish connection between a cable and router, have the router assign local addresses, and therefore, reconnect the Mac to the internet.

(Added 09.22 - EDST:
Omitted from my earlier posts.

You may have to reset each the router (see your device's documentation or related web site for details) and Airport Express, via their respective 'reset' switch. This returns each device to its default settings; deleting any setting changes you may have made.

Also, in my first reply, referrring to Step 02. - 'Connect the Mac directly to the router.'; there are times when I would suggest first connecting the Mac directly to the modem (maybe, turning both OFF, then the modem ON, then the Mac ON), and verify that Mac has established an internet connection. Once an internet connection was established, I would then connect the cable modem to the router, and the Mac to the router (with the modem, router, and mac turned OFF), and continue from Step 04. ...

Port Forwarding:
To set up port forwarding, for say P2P applications, does not require configuring a router to present static IP addresses. One merely enters a port or range of ports (a start port number and a end port number) into the router's respective web page.
Since the router's manufacturer and model number were not provided, nor was the meaning of, reason for, opening 'all the necessary ports' - specific router and / or Airport Express set up solutions are not possible.

Here is a link to 'NetGear'. From here one can learn about UPnP, Port Forwarding, and DMZ - and how to configure a NetGear router accordingly.
The Airport Express would have to be configured similarly.