Business Superhub, routed subnet and Airport Extreme
 

Hi,

I'm looking for a little help here. I have a 50M business broadband connection from VirginMedia with 5 static IP addresses. I'm using the supplied SuperHub (with the business firmware, which is different to the consumer firmware, apparently - mine says V5.5.2R04-BU).

If I assign static IPs to a couple of Macs and plug them into the SuperHub via ethernet, they can access the internet perfectly.

If I assign a static IP to my Airport Extreme (behind which sits the rest of the network), I can't get from the AE to the internet. The SuperHub is in bridge mode because I have static IPs and my Airport Extreme provides DHCP to my internal network.

Weirdly, the following works:

- Ping from one static IP Mac to the other
- Ping from the static IP Macs to the Airport's static IP
- Ping from anywhere on the Airport's internal network to either static IP Mac

Simply put, nothing can route out of the Airport's internal network to the internet.

I would appreciate any suggestions that anyone might have.

Thanks,
Fraser

Re: Business Superhub, routed subnet and Airport Extreme
 

If you temporarily give the same static address you have given the Airport to a Mac does that get full internet access?

Is the Airport configured to provide NAT? if not that will be your problem - you need a device in that config that will provide NAT services to those devices that are not on publicly routable IP addresses. The superhub is not in NAT mode in this config so it won't do that.

Re: Business Superhub, routed subnet and Airport Extreme
 

Could it be a default gateway issue on the AE? What is it set to on the Macs and is it the same on the AE? I'm just wondering if the Macs are somehow working it out for themselves but the AE maybe isn't? It sounds like the AE doesn't know where to send packets that aren't on its own subnet which points to DG. The other static Mac IPs will be on the same subnet which means DG is not required when communicating with them since a broadcast will be sent out to obtain their MAC addresses directly, which explains how you can get from the LAN side of then AE to the static Macs but not out on to the internet.

One other possibility, you haven't got the DG in the DHCP settings on the AE set to something other than the AE have you (previous config maybe)? Check your AE clients have their DG set to the AE IP address. [EDIT] Forget that last possibility, you wouldn't be able to communicate with the static Macs from AE LAN clients if the AE DHCP DG setting wasn't the LAN IP of the AE. [/EDIT]

Either way, this smacks of a default gateway problem specifically with the AE especially if you've already eliminated a problem with the specific IP address by following Carmock's suggestion.

[EDIT2] Also check your WAN DNS settings are manually configured in the AE. Obvious I know, but don't overlook anything!