UPC, AirPort Extreme double NAT problem

Qualitymark

UPC have just sent me out a new router. Its wireless was fighting with my AirPort Extreme network, so UPC shut down the wireless on the router and are running it as a normal cable router.

But apparently I have a 'double NAT' problem on the AirPort.

The network is:

The UPC Cisco router

AirPort Extreme 1, downstairs

AirPort Extreme 2, upstairs.

On Airport Utility, the downstairs AirPort Extreme is showing with a red circle with 1 in it on the right (presumably meaning it's the main one of the two), but also with an orange flashing light, while the one upstairs is showing with a solid green light. When I click on the downstairs AirPort Express in Airport Utility, it says there is a 'double NAT' problem.

On the physical machines, the one downstairs - which is plugged by Ethernet from the WAN socket into the Cisco router - also has an orange flashing light.

How can I get rid of this 'double NAT' problem (and what does it mean)? Or really, just how do I fix the problem; I don't care too much what it means.

All help gratefully accepted.

The UPC router is issuing a private IP address to the AirPort Extreme, which is causing the problem. UPC probably sent you the EPC3925 which is the version with internal wireless aerials - I don't know if you can put this one in bridge mode or not. You may be able to get around it by adding the IP address of the AirPort Extreme into the DMZ on the Cisco.

Qualitymark

How can I add the IP address of the AirPort to the Cisco DMZ, Karsini?

You need to log into the Cisco at http://192.168.100.1/ or http://192.168.1.1 - It's in there somewhere but I'm not familiar with the newer routers.

Qualitymark

Ah yes - tried this today but it's looking for a password and userid and won't accept 'admin' and 'password'.

Qualitymark

Qualitymark wrote: »

Ah yes - tried this today but it's looking for a password and userid and won't accept 'admin' and 'password'.

Leave both fields blank, that should let you in.

Qualitymark

So it did. Now, do I want the IP address or the LAN IP address?

You'll want to use the IP address that is being assigned by the Cisco to the AirPort Extreme. It might me 192.168.1.2 or something similar.

Qualitymark

Hm. How do I find out what it is? Looking at the Airport's own info, it gives an address; used that and had it thrown back in my teeth; used the LAN IP address and had that thrown back too.

When set to 'Static IP', these are the fields it offers:

Internet IP Address
Subnet Mask
Default Gateway
Host Name
Domain Name
Primary DNS
Secondary DNS
MTU Size

It might be a good idea to assign a static WAN IP to the AirPort Extreme and enter this into the Cisco. Just use the same IP range as what the Cisco is giving out. It was 192.168.1.x on older UPC routers - again I'm not sure of the EPC3925 but it should be the same.

If it is a 192.168.1.x IP then try this. Just make sure you're setting the WAN IP and not the LAN IP.

Internet IP Address: 192.168.1.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1
Primary DNS: 89.101.160.4
Secondary DNS: 89.101.160.5
MTU Size: 1500

You'd then enter 192.168.1.2 as the DMZ IP in the Cisco configuration.

Qualitymark

Can't see a place to put in the DMZ...?

Qualitymark

Qualitymark wrote: »

Can't see a place to put in the DMZ...?

I think I'm lost, sorry. Not knowing the UI on the current modems is a bit of a bitch.

Qualitymark

Thanks for your help - I'll give UPC a ring again on Monday and talk to them about this; they might be able to help, having your information. You've really been a good help, and sorry for taking up so much of your time.

Stainless_Steel

No no no hang on.

Put the airport stations into bridge mode. Let your Cisco router assign IPs. Job done.

Qualitymark

How do I put the airport stations into bridge mode?

Stainless_Steel

http://gigaom.com/apple/how-to-setup-an-airport-extreme-in-bridge-mode/

Qualitymark

Yikes. Hm. Thanks.