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Adding AirPort Extreme for a separated network?

Hi,


I'm trying to get a network setup in a small office, but the details have me swimming in the deep end with various issues (DCHP, subnet masks, etc.).


Objective:

Configure two separate networks that don't see each other and both provide WiFi, but share the same internet connection.


Setup:

Phone Line>

BEC (5200?) DSL Modem/Wifi Router (w/ 4 Cat5 ports)>

AirPort Extreme (7.7.3)


Dream:

Connect to the printer from both networks. The printer is currently hard-wired into one of the BEC ports.


Many thanks for any help (or clarifying questions).


Z

Posted on Apr 21, 2015 12:07 PM

Reply
17 replies

Apr 21, 2015 12:17 PM in response to ZhengZhuShip

Sorry, but you can't have both goals at the same time. That is, you cannot have two "separate" networks and be able to access network resources from one to another. At least not with your current equipment. You only option would be to have an additional printer on the other network subnet.


In order to reach your goals you would need a router that support VLANs. The Apple routers do not. It may be possible that your BEC gateway does; however, I am not familiar with this brand to be able to offer any advice.

Apr 21, 2015 4:46 PM in response to ZhengZhuShip

If you already have the AirPort router and want to try to set it up as a separate network.....so that devices on one network will not be able to "see" devices on the other network......the AirPort can normally be configured in that manner. This will meet your first goal, but not the second with access to the printer from the AirPort network.


The AirPort will be in what is known as a Double NAT configuration when you do this. Normally, this will not be a problem, but the only way to know for sure is to try it out and see if things will work the way that you want.


This will require 20-30 minutes of your time and some patience, as we will be setting things up in a non-standard way. Post back if you want to give this a try and need some help with the setup.

Apr 21, 2015 6:50 PM in response to ZhengZhuShip

Sure, the first step would be to get the AirPort set up "normally" in Bridge Mode with your BEC modem/router. To do that, we need to know whether you will be using a Mac or iPhone/iPad to set up the AirPort Extreme.


Once the AirPort is setup "normally", meaning that it will be on the same network as your BEC device, then.....we'll change a setting or two to set up the AirPort as a router on its own subnet.


This may involve some trial and error, since Apple's utility will do its best to set things up the way that it thinks they should be setup.....which is not the same as the setup as you will need.

Apr 21, 2015 7:16 PM in response to ZhengZhuShip

OK, thanks for the information.


Before we change the Router Mode setting of the AirPort to DHCP and NAT, we need to understand what IP address range that the BEC modem/router is using.....to make sure that the AirPort will not try to use the same range.


So, the first thing that we need when you are back in the office is for you to......


Open AirPort Utility

Click on the AirPort Extreme icon


That will display a smaller window with the name of the AirPort Extreme, the name of wireless Network that the AirPort is providing and some other info. We need the IP Address just under the Network listing. We do not need the LAN IP Address......just the IP Address.


Most modem/routers use a 192.168.xxxx.xxx range, but yours might be different.

Apr 22, 2015 7:57 AM in response to ZhengZhuShip

OK, thanks. The AirPort routers use the 10.0.1.x range, so there will not be any chance of an IP address conflict between the two routers on your network.


Open up AirPort Utility again, click on Edit in the smaller window that appears, then click the Network tab at the too of the window

Change the setting for Router Mode from "Off" (Bridge Mode) to DHCP and NAT


You may see a message about Setup over the WAN port on the AirPort, just click to ignore that, then click Update at the lower right of the window and give the AirPort a full minute to restart.


The following step is optional, but recommended if you can do it

Power off the AirPort by pulling the power cord and also power down the BEC modem/router

Wait a minute, then start the BEC modem/router and let it run a minute or two

Then, start the AirPort and let it run a minute


At this point, the AirPort will display a slow, blinking amber light.


Go ahead and test a few devices to make sure that they can now connect to the AirPort wireless and get a good Internet connection. Also check to see that they cannot "see" any of the devices on your 192.168 network and vice versa.


Post back on your progress, please.

Apr 22, 2015 10:24 AM in response to ZhengZhuShip

Please check the settings again. Double NAT is what you want to see once the AirPort restarts.


Also check to make sure that the Ethernet cable from your BEC modem/router connects to the WAN "O" port on the AirPort. It cannot connect to the LAN <--> port on the AirPort


I just performed the same setup here on the network as a test and I have no trouble with the AirPort getting an Internet connection in the Double NAT setup.


User uploaded file


The WAN IP address using the same 10.0.1.x range as the "main" network, while you can see that the LAN address is on a different subnet.....10.0.5.x.

Apr 22, 2015 10:29 AM in response to Bob Timmons

I'll give it another try, but am going to wait until everyone is cleared out of the office.


In the past, when I was getting the Double NAT warning, there was also no internet connection coming through the upstream router. I understood that this was because of DCHP conflicts with the BEC router. Is there a tweak that enables the Double NAT situation to work?


Z

Apr 22, 2015 10:48 AM in response to ZhengZhuShip

There are no IP address conflicts with the BEC router.


I suppose it is possible that the BEC will not put up with a Double NAT on the network, but this is rare among modern routers.


The IT guys at some schools purposely program the network to not allow another router to connect to prevent students from setting up their own networks. Not sure it that might be the case with your office network.


Check and see if the BEC settings have a setting for DMZ, also known as a "router behind a router" mode. That might be a possibility.


Sorry, I cannot suggest anything more that what I've already done......which has worked here in the past with routers from Cisco, Netgear, and also another Apple router setup, which I just tested a few minutes ago and it works fine.


You may need to look at the VLAN option on the BEC, which the Apple router unfortunately will not support.

Adding AirPort Extreme for a separated network?

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