Airport Express questions

[fishrtheone]

Hello,

The situation is this: I am currently paying for cable internet connection, with MAC address filtering, meaning only one of my device can connect at one time (unless of course I spoof, but still, one device each time only).

My question is, if I use Airport Express, which to my knowledge, have it's own MAC address, can I bypass this limitation? i.e ISP -> Router -> Airport -> multiple device?

thank you.

 

[drsox]

Most Internet connections will work with a Router (which Airport Express is) managing the NAT process that converts one "external" IP address into multiple "internal" IP addresses.

I am supposed to connect only one device at a time but I've been able to bypass that for 10+ years with a Router.

Is the Router in your description provided/owned by the cable company or by you ? If it is yours then you should be able to test this without the need for an Airport Express. If it isn't yours then I can understand why it has been configured to be restricting your access.

If you add an AE to the config, then you will have two routers, one behind the other. As long as you connect everything "inside" to the AE and don't have two DHCP servers active, then it will work (I'm pretty sure).

 

[fishrtheone]

Thank you for the reply, much appreciated. I don't understand a few things, can you explain in with lesser technical terms?

1. Currently the router is my ISP's, so everything is locked
2. So if I just connect an ethernet wire to the router connecting it to the airport express or should I get another ethernet wire connecting from my ISP to the Airport express?

I hope I made sense.

 

[drsox]

OK.

At the back of the ISP's router there should be at least 1 ethernet socket for connecting to your local devices.
Connect an ethernet cable to this socket and to the WAN socket of the Airport Express (the socket with the circle above it)

Now get another ethernet cable and connect this to the LAN socket of the AE (the socket with the <-> above it).
Connect the other end to your local device. If you want to connect more then 1 local device by ethernet, then connect a switch to the AE instead and connect the local devices to the switch. Any WiFi connected local devices can also connect to the AE.

The tricky part is going to be the settings on the AE. Try using DHCP as the AE setting on Airport Utility>Internet>Connect.
This should give the AE an IP address from the ISP router. Then use DHCP & NAT for the AE on Airport Utility>Network>Router Mode.
In Network Options, select a range of network addresses and network (10.0.x.x or 192.168.x.x etc). Make sure it's a different network to the one given out by the ISP router. Also make sure that the Enable NAT Port Mapping Protocol is checked.

That should be enough.

 

[Mike in Kansas]

After you've done all that, sometimes you have to reboot everything to get all of these settings and IP addresses to work. Turn everything off, then start with the device closest to your cable data line and turn that on. Wait until it is set up and working (60-90 seconds) and then turn on the next device from your cable data line.

Based on your description, the router you have from your ISP is probably also a cable modem, unless you left that out of your list of devices. You have to use its modem at least; going from the router into Airport Express will keep one MAC address facing the cable company, but allow you plenty of local MAC address for all of your devices.

 

[drsox]

Yes, I forgot.
Make sure to reset EVERYTHING in the order suggested.
If there is a mix of Wired and WiFi, do the Wired first.

PS, there might be another problem if you somehow had to indicate to the ISP's router what the MAC was of the "allowed" device. If you don't remember doing this originally, then you should be OK. Have you tried changing the device connected to the ISP's router ? Was there a problem ?

 

[Killerbob]

I do not have an answer, more a follow up question;

I also have an ISP which uses a modem (Pace V5500), which provides DHCP and NAT, and I have the "Double NAT" message on my Time Capsule (which is providing DHCP and NAT "internally"). How do I get rid of the "Double NAT" situation?

I have the ISP modem connected LAN -> WAN on the TC, and my Macs connected to the LAN ports and to WiFi on the TC.

/Bo

 

[drsox]

I do not have an answer, more a follow up question;

I also have an ISP which uses a modem (Pace V5500), which provides DHCP and NAT, and I have the "Double NAT" message on my Time Capsule (which is providing DHCP and NAT "internally"). How do I get rid of the "Double NAT" situation?

I have the ISP modem connected LAN -> WAN on the TC, and my Macs connected to the LAN ports and to WiFi on the TC.

/Bo

You probably have NAT and DHCP also enabled on the Time Capsule. I don't have a Time Capsule, but I guess it is an Airport Extreme with a HardDrive installed. In AE, under Network there is DHCP and NAT selection. Change that to BridgeMode (you must also have Internet set to DHCP). This assumes that the modem provides internal DHCP as well as external NAT.

What is happening now seems to be that the Modem AND the AE are providing NAT. You need to disable the AE's NAT. If that doesn't work then you may have to try to disable the modem's NAT. Are there any other selection options ?

 

[Killerbob]

Hi,

That's what I figured as well, that I have to turn off DHCP/NAT on the TC, and that was easy enough, but I just wonder if it would be better to find a way to have the TC act as the centre of it all? I can't seem to turn off DHCP/NAT on the modem, that only screws it all up, and internet doesn't work. If I turn DHCP/NAT off on the TC it seems to work - just not what I wanted.

/Bo

 

[drsox]

Hi,

That's what I figured as well, that I have to turn off DHCP/NAT on the TC, and that was easy enough, but I just wonder if it would be better to find a way to have the TC act as the centre of it all? I can't seem to turn off DHCP/NAT on the modem, that only screws it all up, and internet doesn't work. If I turn DHCP/NAT off on the TC it seems to work - just not what I wanted.

/Bo

It seems to me that the ISP modem isn't only a modem, it's a router as well (which TC also does). If this is the case then, yes, TC isn't adding any value to the networking process. Are you sure that the ISP modem is giving out IP addresses for internal connected devices ?

What did you want TC to do ?

Does having a double NAT still allow the TC to function and can you still access the internet etc ? Do internal connected devices get a valid IP address from the TC even when double NAT is in place ?

 

[Killerbob]

You're right, the ISP modem is a router too, and yes it currently is setup to provide HDCP/NAT, and when I turn the TC into "Bridge" mode, then the ISP modem provides IPs to all devices, via the WiFi/Ethernet on the TC - that works fine.

It is just that I wanted to control the process, the IP ranges, assignments, and in my logic it is not an issue to have Internet -> ISP Modem (external IP)-> (external IP) TC (Internal IP) - (Internal IP) Internal devices, with the redundancy that creates. But, the TC reports "Double NAT", and supposedly that is bad. It works fine; all devices get an IP from the TC, they can all see the internet and each other, but there is this nagging feeling that something will not work, and I just wonder what?

/Bo

 

[marzer]

You're right, the ISP modem is a router too, and yes it currently is setup to provide HDCP/NAT, and when I turn the TC into "Bridge" mode, then the ISP modem provides IPs to all devices, via the WiFi/Ethernet on the TC - that works fine.

It is just that I wanted to control the process, the IP ranges, assignments, and in my logic it is not an issue to have Internet -> ISP Modem (external IP)-> (external IP) TC (Internal IP) - (Internal IP) Internal devices, with the redundancy that creates. But, the TC reports "Double NAT", and supposedly that is bad. It works fine; all devices get an IP from the TC, they can all see the internet and each other, but there is this nagging feeling that something will not work, and I just wonder what?

/Bo

Nope. Nothing bad about Double NAT. You can run that way indefinitely without issue. If you can, just tell the TC to ignore the error. The only thing it interferes with is using UPNP, and if you don't know what that is then no worries, your probably not using it

 

[Killerbob]

If you don't know what that is then no worries, your probably not using it

I like that! I did hear that sometimes it can be a challenge to get through the ISP Modem -> Time Capsule layer from the outside, when trying to remote connect to a Mac, if there are two Routers with DHCP and NAT involved. Is that not true?

 

[marzer]

I like that! I did hear that sometimes it can be a challenge to get through the ISP Modem -> Time Capsule layer from the outside, when trying to remote connect to a Mac, if there are two Routers with DHCP and NAT involved. Is that not true?

Yes. My experience is that if you have two NATs in line, UPNP doesn't function properly. So if you need UPNP to work, let the outer most router provide NAT and the others behind it to be placed in bridge mode.

Or if you want your own router to provide all service, put the ISP router in transparent mode. That makes the TC the outer most boundary to your network to allow control of all services as you mentioned. Just be aware, Apple routers do not allow you to disable the ping response. Not that its a critical security risk but does make you more easily visible to scanning.

 

[drsox]

I also suggest you ignore the double NAT. It is a well known way of providing isolation between a 2 networks to use double NATs. Ignore the TC error or, if you can, set the ISP device to be modem only (but you said that was not possible)