Why does my airport give wrong default gateway dhcp?

Question

I have a fancy AirPort Extreme Base Station running 7.7.3.
It was recommended as a very good wireless access point, which it is, purely in terms of signal strength and connectivity.
In terms of easy configuration, this thing is a nightmare. Someone once told me, "Get Apple products, they just WORK!" Not in this case. I am using the base station to provide access on my home network wirelessly and wired on the same layer 2. DHCP is assigning 192.168.1.250 as the default gateway, but the IP of the base station is 192.168.1.1, so none of my hosts on DHCP are able to get Internet. I cannot find or see a way to correct the DHCP gateway assignment.
In addition, I have a single wired Windows host. It does not get the DHCP reservation I set up for it. I cannot for the life of me figure out why. MAC is right. ipconfig /release and /renew fails to assign the correct address every time tho.
I have one Mac in the house. It too fails to obtain the right gateway IP. My question: why is the base station assigning 192.168.1.250 as a gateway when it's own internal IP is 192.168.1.1????
I have owned many home access points. This is the first one I couldn't assign the internal IP to as a gateway address, and I can't assign a specific subnet mask to pair down the broadcast domain. Why are the options to configure my internal network so limited?

Answer 1

LaPastenague wrote:
Why are the options to configure my internal network so limited?
So it will be easy to configure.
Sadly this means there is no way to fix things when they go wrong.
How did you manage to get 192.168.1.x .. as the default IP of the TC is 10.0.1.1 and it is well worth leaving it alone.
Post a few screenshots and we can help you fix it up. Mostly.. probably.
So the default is 10.0.1.1, but I didn't want an entire class A range wide open on my home network, so I chose the class C 192.168.X.X (why is Apple still doing classful networks?!?)
Here's some helpful screenshots, starting with the opening screen.... note the router's IP:
This is my AirPort's basic info, and the networks. There are two ethernet ports in back, one connected to the cable modem, the other to BADGER, my PC. BADGER will be the example in all my DHCP woes...:
This is BADGER's manually assigned IP info. I would like to set up a reservation for it on the AirPort so I can just switch it to DHCP and be done.
As you can see, my gateway is 192.168.1.1, which is the internal IP of the AirPort extreme. I use public DNS servers, so I add those manually on the PC. So, using this info, I create the reservation:
Here you can see the DHCP scope I've assigned: .1.2-.1.50. I also set up a reservation for BADGER. No where on here is a way to specify the router's internal IP, which is 192.168.1.1 - it's the only gateway address that works.There's also no way to apply a more restrictive subnet mask to limit the number of hosts on my internal side, but that's another issue. Moving on...
I apply the reservation. I click update. The AirPort extreme router updates itself. I switch BADGER to DHCP, and release/renew. Here's where it gets interesting:
Here's what the router wants to assign me. The MAC address is the same as in the reservation, but the AirPort Extreme gives me 192.168.1.129? That's not even in the range I defined. Also, note the gateway address. It wants to assign 192.168.1.250 ... but that's wrong, as indicated by the lack of network connectivity in the system tray. If I configure my PC to use 192.168.1.1, then traffic routes off my home network just fine because that's the internal IP of the AirPort Extreme. So, without getting into this product's shortcomings as an actual configurable home router:
- Why does it assign its gateway as 192.168.1.250 when it's really 192.168.1.1?
- Why does it ignore my DHCP reservation and assign a completely out-of-scope IP?
All of my devices are getting .250 as the gateway. Wireless and BADGER, even my lone Mac. Can anyone shed some light?